Caiman

SPECTACLED CAIMAN NATURAL HISTORY APPEARANCE The spectacled caiman (Caiman crocodilus) is one of five caiman species in the Amazon River drainage system. This species has a typically crocodilian appearance, but its maximum size is rather smaller than the black caiman and other members of its family. The largest males reach about 8 feet (2.5 m) but average about 6 feet (2.1 m). Females are about two thirds the size of males. The name "spectacled" comes from a bridge between the orbits of the eyes that looks rather like a pair of spectacles. The upper eyelids bear bony ridges, conferring a dinosaur-like appearance. Adult spectacled caimans are uniformly olive-green whereas juveniles are khaki green with yellow and black bands along the stomach and base of the tail. As with other crocodilians, this camouflage becomes less distinct in the adult. Of particular note is this species' chameleon-like ability to change color. Although the effect is subtle, other crocodilians show this ability, which arises from migration of black pigment in skin cells. Caiman crocodilus is classified into several different subspecies which vary in size and skull morphology, as well as skin color. HABITAT AND DISTRIBUTION The spectacled caiman is the most widely distributed crocodilian in the Americas. It is found throughout the Amazon River basin from southern Brazil up through Central America to southern Mexico. The far west of its range is limited by the Andes mountain range in Peru, but more northerly, in Ecuador and Colombia it is found to the Pacific coast. This species prefers quiet riversides and swampy areas where it lurks among floating vegetation, although it might be found in any wetland habitat. FEEDING AND DIET The spectacled caiman is an opportunistic predator, taking advantage of whatever prey is most abundant. Its main diet comprises fish, although adults are known to take large mammals such as capybara and peccary. As juveniles grow in size, they graduate up to approriately sized prey. They begin with tiny aquatic invertebrates (insects, crustaceans, molluscs). Larger juveniles prey on various vertebrates such as fish, amphibians, reptiles and water birds, that make an increasing proportion of the diet. Only mature caiman are able to tackle large mammals. Caimans adapt to prevailing environmental conditions and during the dry season, decrease predatory activity. In dire situations they may resort to cannibalism. As top predator caimans play a pivotal role in the balance of the ecosystem. In the absence of a top predator, prey species' populations can veer out of control and cycle wildly. Dominant species tend to take over. Where caimans are heavily hunted, some researchers have reported that piranha numbers tend to be higher. Caimans also serve as a conduit for cycling nitrogen through the ecosystem, as their waste serves to fertilize aquatic plants. (Nitrogen

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is an essential nutrient for plant growth.) BREEDING Caiman reproduction is closely matched to the Amazon's annual cycle of wet and dry seasons. Eggs (of females) and testes (of males) grow larger as the rainy season draws near around May. From May to August, caiman courtship and mating behavior peaks. Egg-laying follows, taking place mostly between July and August. Close by the river's edge, Females dig a shallow pit in sandy soil with their front legs and lay 15 to 50 eggs. Clutch size averages 25. This is then covered with a mound of dead leaves, reeds and grasses. Heat from the nest's decaying vegetation helps maintain the nest at a constant temperature. Unlike most animals, the sex of baby crocodiles (and some other reptiles) depends on the temperature in the nest, temperaturedependent sex determination (TSD). A warm nest will result in more males, whereas a cooler nest skews the ratio toward females. The location of the nest can therefore influence the numbers of males and females that hatch. A nest under cover will have more females than a nest in the open. The phenomenon may prove useful in reptile conservation since the developing eggs can be treated with sex hormones to result in a majority of females. Females sometimes nest in groups, even sharing nests. This spreads the risk for females since a nest predator will be less likely to take all the eggs of a particular female. Eggs may be eaten by lizards such as the tegu (Tupinambis spp.) which often destroys the entire nest and may damage four fifths of nests in its range. To reduce damage caused by predators the female caiman lurks close by and will chase off a potential marauder. Due to the seasonal timing, young caiman have abundant prey upon hatching, about 90 days after laying. Females provide a degree of parental care as the juveniles stay in here vicinity until they are large enough to fend for themselves. Groups of females that shared nest sites may also share in caring for young. Female caiman breed between 5 to 10 years of age, once they have reached 3 or 4 feet in length. Males reach sexual maturity at a larger size but as they grow faster, are capable of breeding at the same age. The social rank of the individual determines breeding success since lower rank animals feed less and grow more slowly, hence take longer to reach breeding age. CONSERVATION With a wild population estimate in excess of 1,000,000, the spectacled caiman is the commonest of all crocodilian species, but is locally threatened in many parts of its range. It's not hard to hunt caiman. A hunter patrols a river bank at night, shining his flashlight among the reeds, looking for a lurking caiman's tell-tale eye, shining red like a hot coal. He just shoots in the right direction, waits for the thrashing to stop and motors over to hitch the dead animal into his boat. For tourists hunting caiman, the procedure is a bit more complicated. The tricky part is to approach cautiously, while all the time keeping the flashlight on the bright red spot. This apparently mesmerizes the beast. If all goes according to plan, the caiman will remain paralyzed by the light while the boat approaches. The guide will then lean over the boat, hanging on to whatever is to hand, to grab the hapless creature. After a round of picture taking and brief overview of caiman natural history, the captive is released to no apparent ill-effect. Ecotour operators hope this victimless hunting will pay off as the close encounters help educate and inform about these beautiful

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creatures. Excessive hunting of other caiman species (such as the black caiman) has helped the spectacled caiman, which has moved into its competitors' habitat. Most of the spectacled caiman's hide is too rough to make good leather. Only the sides are suitable, so they were not as intensively hunted as other species. This changed as those species became rarer, so to supply the trade, more spectacled caimans were hunted. Today this species provides most of the crocodilian leather used in the United States. Illegal hunting fuelled by rising demand in Asia is the main threat. However, the species' adaptability, high reproductive rate, and the increase in habitat resulting from human activities (e.g., dams), have dampened the effect of excessive hunting. Conservation of caimans is complicated by taxonomy (classification) which has yet to be fully resolved. Morphological studies have led to the recognition of several sub-species, some of which are not accepted by experts, others are. Because conservation decisions often depend on a desire to preserve particular species, such information is essential in creating reserves and parks that will do the intended job. Populations in the Brazilian Pantanal, Colombia and Venezuela seem relatively healthy, although Central American populations seem severely depleted. Wildlife managers question the long-term prospects for farming and ranching of caiman populations, although such programs have succeeded in Africa with the Nile crocodile. The limited utility of the spectacled caiman's hide means a lot of animals are needed to meet demand. The best approach to long-term conservation of caimans may be the creation of sustainable use preserves that permit regular culling of local populations. This may provide an income for local people as well as incentive to conserve natural habitat.

Links Florida Museum of Natural History: Caiman crocodilus Reptile Conservation International Gulf States Marine Fisheries Commission: Caiman crocodilus (Linnaeus) Wikipedia: Spectacled caiman Digimorph: Caiman crocodilus (spectacled caiman): skull Wikipedia: Alligatoridae FAO: 3.3.1 Caiman crocodilus (spectacled caiman) herpbreeder.com: Crocodiles of the World - Caiman ITIS Report: Caiman crocodilus crocodilus (Linnaeus, 1758) Institute for Tropical Ecology and Conservation: Caiman crocodilus Narrow-snouted Spectacled Caiman The Taxonomicon: Caiman crocodilus taxonomy CITES: Colombia - Export of Skins of Caiman crocodilus Zoofarm de Colombia: The Spectacled Caiman Geological Society of America: Triche, Nina E., Osteological and Ontogenetic Variation in Caiman crocodilus The Herpetologists' League 2001: Stephen D. Busack and Sima Pandyab. Geographic Variation in Caiman crocodilus and Caiman yacare (Crocodylia: Alligatoridae): Systematic and Legal Implications. Herpetologica 57(3): 294-312 Calderon M.L., De Perez G.R., Ramirez Pinilla M.P. (2004) Morphology of the ovary of Caiman crocodilus (Crocodylia: Alligatoridae). Ann Anat. 186(1):13-24.

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Ebbesson S.O., Goodman D.C. (2001) Organization of ascending spinal projections in Caiman crocodilus. Cell Tissue Res. 215(2):383-95. Mainly photos Animal Diversity Web: Caiman crocodilus (spectacled caiman) wildherps.com: Common Caiman Photovault: Caiman (Caiman Crocodilus) Paleosuchus bnoonan.uta.edu: Caiman crocodilus (Linnaeus, 1758) About.com: South America Wildlife Photo Gallery, Jacaré - Caiman crocodilus Michael Rothhaar, Ag Krokodile

3.3 Caimans (from FAO document) 3.3.1 Caiman crocodilus (spectacled caiman)

Numbered among the neotropical fauna are nine species of crocodiles or caimans. Once abundant in the rivers, lagoons and swamps of tropical America, the extensive commercial hunting for their hides that began in the 1920s or 30s has now relegated them to islands of residual populations (see 2.4.2.1). Most of the prized crocodilians are endangered species (Table 23) in urgent need of protection and recovery measures such as strictly protected areas or captive breeding. Among the less persecuted species, dwarf caiman (Paleosuchus) are fairly important in indigenous subsistence hunting, but their low numbers, small size and heavily ossified skins render them of little commercial value. The spectacled caiman (Caiman crocodilus), also known as C. sclerops (16, 377), is the only species now locally abundant, of some commercial value, and conceivably an exploitable resource in specific regions.

3.3.1 Caiman crocodilus (spectacled caiman) Local names: Alligator (Guyana, Trinidad), baba (Venezuela), babilla (Colombia), yacaré, yacaré tinga (Brazil), Kaaiman (Suriname), lagarto, lagarto chato (Mexico, Central America), lagarto blanco (Ecuador, Peru), yacaré cascarudo (Argentina), yacaré jhu (Paraguay). Geographical variation and distribution: This is the most widely distributed American crocodilian, ranging from Mexico to Argentina. Brazaitis (77) recognizes four subspecies: Caiman crocodilus fuscus from Oaxaca on the Pacific coast of Mexico down through Central America to northern Colombia and the Maracaibo basin in Venezuela; C. c. crocodilus found 4

in the Orinoco river basin, Amazonia, the Guianas and the island of Trinidad; C. c. apaporensis, only on the Apaporis river in southeastern Colombia, and C. c. yacare (103, 141, 377) in southern Brazil including the Mato Grosso, Bolivia, Paraguay and northern Argentina. Elevational range: C. crocodilus is restricted to the tropical lowlands; the limits of its range coinciding with the annual isotherm of 24°C (118). The highest reported sighting was at 800 m in Colombia (377). Size and weight: The spectacled caiman varies by size and weight according to sex, age and locality. The total maximum length reported by Medem (377) was 240 cm for males and 173 cm for females, with maximum weights of 45 kg for males and 19 kg for females. Maximum sizes and weights reported for males in the Venezuelan llanos were 231 cm and 58 kg, and for females 161 cm and 20 kg (31). Most adults grow to 120-200 cm, and weigh 7-40 kg. Mexican spectacled caiman, sometimes referred to as C. crocodilus chiapasicus, may be smaller (16) compared to C. crocodilus yacare, which can reach 250 cm and weigh 58 kg (males). Adult females can weigh up to 14-23 kg (140). Habitat: C. crocodilus can be found in a variety of habitats from rivers, creeks, lagunas and estuaries in forest or savannah areas to bogs and brackish mangrove swamps in coastal areas (16, 31, 377, 531, 599). They prefer calm, often turbid waters, with floating or emerging vegetation. Most habitats have marked seasonal flooding and dry periods, the animals congregating in the remaining bodies of water during the dry season. Which part of the habitat caiman use and when depends on their age and sex (31, 531). Table 23. Synoptic table of Latin American Crocodilia; sources of information: 16, 31, 77, 103, 377, 378 Species

Local

Total length (cm)

Geographical

name

maximum length

distribution

Commercial IUCN status value

(246)

medium

vulnerable

high

endangered

high

endangered

in parentheses Caiman

baba,

150-200 (250)

From Oaxaca, Mexico

crocodilus

babilla

through Central America

(spectacled

lagarto

and south to the River

caiman)

amarillo

Paraguay and Argentina

jacare tinga Caiman

jacare de

latirostris

papo

200-250 (300)

Western Brazil from Rio Grande do Norte to

(broad-snouted amarelo

northern Uruguay

caiman) Melanosuchus

jacare acu

niger

caimán

300-400 (500)

Amazon River basin in Brazil, Bolivia, Guyana,

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(black caiman)

negro

Colombia and Peru

Paleosuchus

jacare

palpebrosus

coroa

through Venezuela

(dwarf caiman)

cachirre

Guyana and to southern

90-120 (200)

From southern Colombia

low

Brazil Paleosuchus

jacre coroa

100-130 (226)

trigonatus (dwarf caiman)

From southern Colombia

low

and Venezuela to Bahía, cachirre

Brazil, Peru and the Bolivian Amazon

Crocodylus

cocodrilo

300-400 (700)

Pacific slope from

acutus

de río

Nayarit, Mexico to

(American

caiman de

Torbes, Peru. Atlantic

crocodile)

la costa

slope from Florida to

high

endangered

high

endangered

high

endangered

high

endangered

Venezuela Crocodylus

caimán

400-450 (678)

Orinoco River basin in

intermedius

llanero,

(Orinoco

caimán del

crocodile)

Orinoco

Crocodylus

cocodrilo

moreletii

de

Tamaulipas, Mexico to

(Morelet's

pantano

Guatemala and

Colombia and Venezuela

100-150 (250)

crocodile)

Atlantic slope from

Honduras

Crocodylus

cocodrilo

rhombifer

perla

200-250 (350)

Cuba

(Cuban crocodile)

Abundance: The easiest way to estimate spectacled caiman population density is by night counts during the dry season ((31, 530, 531). The average variation in population densities (No./ha of water surface) on 19 farms in the Venezuelan llanos ranged from 57 to 1 119, and crude density (No./ha of farm area) from 0.07 to 15.4 (31, 530, 562). These figures are exclusive of animals under the age of one and most represent population saturation. Vásquez (599) cites specific population densities of 0.77-8.22/ha in the Peruvian Amazon. Behaviour: The spectacled caiman, like other crocodilians, is mainly static, preferring to remain immobile and partially submerged, or to bask on the shores, particularly in midmorning and early afternoon (except on overcast days) (31, 530). Despite the animal's apparent immobility, situations calling for a fight/flight response or the presence of potential prey can elicit very rapid and agile movement. Spectacled caiman feed in the water at any time, but mainly at night (16, 377). Adult males turn aggressive and, apparently, territorial at the onset of the rainy season and of heat. They are fairly unsuspicious in quiet habitats but

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timid where they have been hunted (377, 387). They have 13 visual and nine voiced patterns (31). Feeding habits: Neonates feed on aquatic and terrestrial insects, expanding to include crustaceans, molluscs and fish as they grow. The basic adult diet varies from place to place, and includes fish (478, 562) and crustaceans (16, 599), or a combination of molluscs, crustaceans and fish (31, 377). Full-sized adults also prey on mammals, semi-aquatic or aquatic reptiles, and birds. They also eat carrion. Reproduction: C. crocodilus takes at least six years to reach sexual maturity, corresponding to an approximate overall length of 114 cm (approximately 60 cm snout/vent) (242). Courtship and mating coincide with the onset of the rains. The female then builds her nest a mound of earth and plant matter, some 40 cm high and at least 1 m in diameter - on a site near water but not subject to flooding, often building over an earlier nest (31, 140). She lays a clutch of eggs, usually at peak flooding, which is July-August in the llanos (377, 562) and January-February in the Colombian Amazon (377) and the Pantanal de Mato Grosso (140), although this is apparently not the definitive pattern for all sites (377, 599). The number of eggs ranges from 12 to 44 with a mean clutch size of 29, depending on female body size (497). During the 65-84 day incubation period (various authors), the female guards the nest. The hatchlings emerge with the oncoming dry season, measuring 20-23 cm in length (16, 140, 503, 562), and the mother remains with them during the first few months of life. Mortality: Despite maternal care, there is nest depredation by coatis (140), Tegu lizards (148, 562) and other animals, and some nests are destroyed by flooding, trampling or human interference (egg collecting). A bare 20-25 percent of the eggs hatch successfully (31, 140, 148, 562 and 563). Hatchling predators include wader birds, raptors and other carnivores, and almost all die before the age of one year. Adult mortality, on the other hand, is thought to be extremely low (31, 148). Hunting: Spectacled caiman are usually hunted at night from canoes, as the hunters can get much closer than in the daytime and can easily find the animals by their eyes which shine red in the torch beam. Rivero Blanco (468) reports on the principal technique in the Venezuelan llanos: by day the animals are herded into a section of the lagoon where they can be easily captured. Animals of legal size are then harpooned, pulled ashore with ropes and finished off with clubs. They are easier to catch in the dry season when the waters have receded. They are hunted with harpoons, rifles or shotguns. The traditional harpoon with a wooden handle and detachable head attached to a strong rope that comes off in the prey requires more skill and less distance on the part of the hunter, but it does avoid the loss of wounded animals that is so frequent when caiman are hunted with guns (377). Meat-baited hooks with a wire and wood floater are also used (188, 599), and sometimes trawlnets or traps. 7

Products: Some indigenous people (Table 6) (and campesinos to a lesser extent) hunt caiman for its tasty but rather tough white meat, and they may sell it as salted and dried slabs (like fish). It is recommended that animals hunted for their skins also be eaten to increase the nutritional and economic contribution of the species (498). Fresh caiman eggs are a preferred food in the llanos region. Commercial hunting for spectacled caiman skins began on an intensive scale in the 1950s (see 2.4.2). This is currently the only crocodilian that can be harvested in tropical America. To remove the skin the animal is split down the back with a machete or chainsaw so as to preserve the flanks and belly. With medium-sized animals measuring 3-5 feet (91-152 cm), the entire body is used ("coverall" or mantle type). Only the soft leather of the flanks from the throat to the vent (jacket or belt type) is used in the case of the highly ossified big males. The hide is preserved salted and semi-dried and the meat is usually discarded. The commercial value of a legal-size, raw caiman hide at producer level in Venezuela in 1988 was approximately US$50. These prices make caiman harvesting very profitable. Desiccated hatchlings and young are often sold as tourist souvenirs. Management: The establishment of minimum harvest sizes of 120 and 150 cm in Colombia (118), 200 or 150 cm in Peru (281) and 180 cm in Venezuela (603), plus bag limits per hunter (to a lesser extent), have all been used to regulate caiman hunting. Hunters, traders and tanners have all eluded both size and bag limits for lack of supervision, and so most countries in the area have opted for a total ban as an emergency measure. Both indiscriminate slaughter and blanket prohibitions minimize the potential contribution of the species as an exploitable resource. The planning and implementation of rational management and harvesting based on C. crocodilus biology are urgently needed. The features of spectacled caiman life history, as for the other major reptiles, are high reproductive capacity, high mortality at the egg and neonate stage, a long preamble to sexual maturity and low adult mortality. This latter attribute has helped to maintain large stable populations which can partially occupy the niche left vacant by Crocodylus (188, 377, 531). Commercial exploitation of adult caiman has had a very destructive impact on population due to the low capacity for recovery. The impact of density/dependence on population dynamics and growth, as well as the net production rate at whatever density, are apparently unknown. An experimental harvesting programme using wild populations in private farms was recently launched in Venezuela. The population size was first estimated and low harvest rates allowed (7 percent of the population aged one year or over) (Table 17). Complementary and/or alternate measures were 1) the protection of nesting sites; 2) artificial incubation of egg clutches and the captive breeding of hatchlings up to the age of one year followed by release into the wild, and 3) captive breeding up to the age of three years (1 metre total length), slaughter and sale (148, 603). Given the economic importance of the species in Venezuela, both rural producers and reptile leather tanners set up associations in 1987 to promote research, production and sustained utilization, which augurs well for C. crocodilus management. 8

Captive breeding: As a means of combating egg and hatchling depredation, experiments have been carried out with artificial incubation using polyethylene shelters, wooden crates and polyethylene bags as nests, as well as breeding hatchlings in tanks or cages (60, 497, 503). The mean growth of hatchlings fed a variety of diets of animal origin ranged from 1.5 cm (503) to 2.5 cm (497) per month (the individual monthly maxima were 3 cm and 29 g). When group size per tank was increased from 15 to 35, mean growth dropped and individual variations increased. A number of privately owned captive breeding establishments have recently been set up in Venezuela, providing a growing backlog of experience on the maintenance of this species in captivity.

Animal Classification: Crocodilians Sponsored Links Dann Croc Shop Alligator & Crocodile Belts, Shoes Wallet Trafalgar, Crookhorn, Tervis www.Dann-Online.com Home > Library > Animal Life > Animal Classification Family: Gharials Family: Alligators and Caimans Family: Crocodiles and False Gharials (Crocodiles, alligators, caimans, and gharials) Class: Reptilia Order: Crocodylia Number of families: 3 Number of genera, species: 8 genera; 23 species

Evolution and systematics There are 23 widely recognized species of crocodiles, alligators, caimans, and gharials, all members of the order Crocodylia. Superficially they resemble reptiles, yet their closest cousins are birds and extinct Dinosauria, a group known as archosaurs ("ruling reptiles"). Modern Crocodylia are the latest iteration of the Crocodylomorpha, a major group whose evolutionary heritage spans almost 240 million years. Crocodylia are often described as "living fossils," unchanged in millions of years, but this description is inaccurate. The Crocodylomorpha were a diverse and successful group occupying terrestrial, freshwater, and marine ecosystems, and their modern

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counterparts are barely less fantastic. This group is informally referred to as "crocodilians," although the term "crocodylians" technically refers to members of the order. Every successful group has a beginning. The earliest crocodyliforms were terrestrial hunters that shared an ankle with modern Crocodylia, but little else, yet they were dominant predators whose legacy diversified throughout the Jurassic and Cretaceous periods. Their success is evident in excavations, as more crocodyliform material than dinosaur bones often turns up. Discoveries have been remarkable, such as curious peglike teeth and spiked protective plates from Desmatosuchus that indicate a defensive, vegetarian lifestyle. Despite dabbling in herbivory, it was in carnivory that crocodyliforms excelled. The awe-inspiring skulls of Sarcosuchus and Deinosuchus paint a picture of massive killers over 35 ft (10.7 m) in length. From terrestrial beginnings, crocodyliforms branched out into freshwater and marine habitats. In extreme thalattosuchians (marine crocodiles), limbs were replaced with paddles and a fluked tail to compete with sharks and ichthyosaurs for dominance of the sea. However, these marine forms were an evolutionary dead end, and freshwater species with limited marine ability proliferated from the Jurassic onward. Modern Crocodylia first appeared over 100 million years ago, and despite experiments with various and occasionally bizarre forms, the semiaquatic predator has become their signature role. Scientists disagree about crocodyliform classification and evolutionary relationships. In 2003, 23 species of Crocodylia are widely recognized, divided into three families: Alligatoridae (alligators and caimans; eight species), Crocodylidae (crocodiles; 14 species), and Gavialidae (gharial; one species). The Crocodylidae are further divided into two subfamilies, Crocodylinae and Tomistominae. Some taxonomists also divide Alligatoridae into two subfamilies: Alligatorinae and Caimaninae.

Physical characteristics A crocodile may be thought of as an elegant solution to the problem of catching prey, surviving unpredictable environments, conserving limited energy, and reproducing successfully. In appearance, crocodiles superficially resemble lizards, having scales, a long tail, and four limbs. But appearances can be deceptive, and a closer look reveals that crocodilians are unique. All 23 species are broadly similar in appearance, varying mainly in size, scale patterns, color, and skull morphology. The smallest species is Cuvier's dwarf caiman (Paleosuchus palpebrosus); adult males rarely exceed 5 ft (1.6 m) in length and females 4 ft (1.2 m). Within the same family, the black caiman (Melanosuchus niger) and American alligator (Alligator mississippiensis) vie for largest size, yet rarely exceed 14 ft (4.3 m). Crocodylidae range from the diminutive dwarf crocodile (Osteolaemus tetraspis) at 6 ft (1.8 m) to the massive estuarine crocodile (Crocodylus porosus) that can exceed 16 ft (5 m). The sole gavialid, the Indian gharial (Gavialis gangeticus) can also reach 16 ft (4.9 m). Females are always the smaller sex, and this is most apparent in estuarine crocodiles, where females of 10 ft (3 m) are considered to be very large. As the largest living reptiles, males over 16 ft (4.9 m) may tip the scales at 1,100 lb (500 kg), but these are lightweights compared to rare individuals that exceed 18 ft (5.5 m) and 2,200 lb (1,000 kg). Although several species, including estuarine crocodiles and Indian gharials, are capable of attaining such sizes, evidence of these giants is scarce. The largest crocodile reliably measured and published in the literature, an estuarine crocodile from Papua New Guinea, was 20.7 ft (6.3 m) long. While unlikely to be the maximum possible size for this

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species, stories of even larger animals are difficult to verify. One fact is certain—crocodiles over 20 ft (6 m) are exceptionally rare. Crocodilians undergo a dramatic increase in size from hatchling to adult. Over its lifetime, an estuarine crocodile may grow from a 12-in, 2.8-oz (30-cm, 80-g) hatchling to a 20-ft, 2,650-lb (600-cm, 1,200-kg) adult. A 20-fold increase in length and 15,000-fold increase in weight is quite a feat in the animal kingdom. Imagine, then, how this compares with the extinct Sarcosuchus, which reached 35 ft (10.7 m) and over 19,800 lb (9,000 kg)! Growth is most rapid when young, yet scientists are unsure whether adults reach a maximum size or continue to grow slowly until they die. The enormous sizes attained by extinct species such as Sarcosuchus and Deinosuchus may have been possible by maintaining those fast juvenile growth rates throughout a greater percentage of their lives. Crocodilians are covered in a thick, leathery skin broken into various sizes and shapes of scales in particular areas. Scales on the back are large and rectangular, lying in parallel rows from shoulders to pelvis and continuing onto the tail. These dorsal "scutes" each contain a bony plate called an osteoderm ("skin bone") just below the surface. A tough covering of beta-keratin helps minimize water loss, although the more flexible alpha-keratin is found between the scales. Osteoderms not only offer protection, they are infused with blood vessels and function as solar panels, transporting heat from the surface to the body core during basking. Adjacent osteoderms are closely integrated like the beams of a bridge, providing support for the spinal column. Large nuchal plates protect the nape. Scales on the flanks and limbs are generally smaller, rounder, and softer to allow bending. Those on the belly are even, rectangular, and smooth to reduce friction sliding over the ground. Small osteoderms are found in the belly scales of most species. Thick, rectangular scales are present on the tail, with sharp, upwardpointing scutes providing extra surface area as the tail sweeps through water. Scales on the head are small, irregular in shape and thin, housing blood vessels and sensory nerves. Each species has a unique pattern of scales and osteoderms. Deceptively, a layer of mud and dust often covers dry, basking adults, suggesting a bland coloration. However, most species exhibit distinctive color patterns, which enhance camouflage and aid communication. Dorsal color is typically tanned yellow to dark brown, overlaid with characteristic dark bands, spots, or speckles. Juveniles of all species are more vivid, their bright colors fading in adulthood. Ventral scales are creamy white with varying degrees of black pigmentation, except for the almost black bellies of dwarf caimans and dwarf crocodiles. Color mutations where pigment is usually absent are rare, genetic anomalies. Leucistic and albino crocodiles are as tempting to predators as their "white chocolate" appearance suggests, but they are popular tourist attractions in captivity, where they must be shielded from excess sunlight. Both short- and long-term changes in skin color have been recorded in several species. Changes in mood, such as those caused by stress, and environmental temperature can dull skin color. Long-term change can be effected by the environment, with individuals from shaded areas becoming darker as black pigment (melanin) accumulates in the skin. The crocodilian head always draws attention. The skull, although massive and sturdy, is infiltrated with air spaces. These spaces reduce weight without compromising strength, and provide extensive areas for muscle attachment and expansion. Two pairs of openings on either side of the cranium classify the skull as diapsid. There is considerable variation in skull and jaw morphology across all 23 species, and this has an ecological significance: broad jaws are reinforced by bony ridges to resist strong bite forces for crushing prey, while slender jaws slice with little resistance through water to seize slippery prey.

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The head houses all the major sense organs, vital for navigation, communication, and hunting. Senses are concentrated on the dorsal surface, so they remain exposed even when the head is partially submerged. Remarkably, a crocodile can hide its entire body below the water while maintaining maximal sensory input from its surroundings. As masters of stealth and ambush, crocodiles have no equal. The eyes of the crocodile are placed high on each side of the head, turrets that provide 270° of widescreen coverage plus 25° of binocular overlap directly ahead to accurately judge distance. The pupil, round and dilated at night to permit maximum light entry, is compressed to a thin vertical slit during daylight to protect the sensitive retina. Inside the eye, cone cells on the retina provide color acuity by day, and high densities of rod cells give excellent low-light sensitivity at night. These rods can change shape to further alter sensitivity. A layer behind the retina, the tapetum lucidum, is impregnated with guanine crystals to reflect light back across the visual cells. This effectively doubles visual sensitivity at night, and shining a beam of light directly into a crocodile's eye rewards the observer with a fiery red eyeshine. Visual cells are most concentrated in a horizontal band across the back of the retina, a fovea providing highest visual acuity where crocodiles need it most—along the same plane as water. To focus (accommodate), crocodilians change the shape of their lens using the ciliary body. Three eyelids cover each eye. The upper lid contains bony ossification to protect the eye, large bony palpebrals in caimans lending "eyebrows" to their appearance. The lower lid lacks ossification and is responsible for closing the eye. The third eyelid, the nictitating membrane, sweeps laterally over the cornea to clean the eye and protect it from abrasion underwater. Although the nictitating membrane is transparent except for the ossified leading edge, crocodilians still see poorly through it. Lachrymal (tear) glands lubricate its passage via ducts connected to the nasal cavities. Fluids may even accumulate when the crocodile remains out of water—real "crocodile tears," yet an unlikely source for the popular myth. The ears are located immediately behind the eyes, the eardrum protected by an elongated flap of skin. Hearing sensitivity can be altered by opening a slit in front of the flap, or lifting the flap upward. When submerged, the ears normally close, as hearing becomes secondary to the ability to feel vibrations through the water. Detectable frequencies range from below 10 Hz to over 10 kHz, and sound pressure levels below -60 dB can be detected within certain bandwidths. In other words, crocodilians have excellent hearing, on a par with birds and mammals. Peak sensitivities range from 100 Hz to 3 kHz depending on the species, which coincides with the bandwidth of calls produced by juveniles. Vocalization is well developed in crocodilians, with over 20 different call types from both juveniles and adults recognized. Crocodilians can breathe when submerged by exposing the dorsal margin of their head and hence their raised nostrils. Inhaled air passes through sinuses separated from the mouth by a bony secondary palate, where any chemicals in the air are detected by sensory epithelial cells. The presence and direction to food is easily discerned, and smell plays an important role in chemical communication. In early crocodyliforms, the internal nostrils (choanae) opened in the front of the mouth, but over millions of years they moved back to the throat, a phenomenon termed post-nasal drift. The palatal valve, a fleshy extension of the tongue, completely seals the throat from the mouth, hence crocodilians breathe easily near the surface even if the mouth is flooded with water. The glottis, an opening to the trachea and lungs, is located directly beneath the choanae. By varying tension in muscles lining the opening, exhaled air is forced through a constriction capable of relatively complex vocal sounds. Amplification is provided by expanding the throat using the hyoid apparatus, a curved cartilage beneath the glottis. A curious bend in the trachea of several species may further amplify the sound, similar to the long, curved necks of cranes.

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The tongue lies between each mandibular bone of the lower jaw, behind the mandibular symphesis (fusion). Hence in slender-snouted species with extended sympheses, the tongue is greatly reduced. Although relatively immobile, the tongue can be pushed against the roof of the mouth to manipulate objects or pulled down to create a pouch for hatchlings. Typically bright yellow or orange, the tongue's color may provide a social or warning signal when the jaws gape. Pores cover the surface of the tongue, through which "salt glands" produce a saline fluid in brackish or sea water in Crocodylidae and Gavialidae. Alligatorid pores play no role in salt secretion, supporting theories of a more recent marine dispersal phase for the Crocodylidae. Chemoreceptors lining the tongue detect chemicals in water, yet little is known of their sensitivity. Their importance is implied in their ability to detect food underwater, and in the role of pheromones secreted from chin and paracloacal musk glands. High densities of dome pressure receptors (DPRs) cover scales on the head, particularly around the jaws. Disturbances of the water surface create pressure waves easily detected by DPRs, rapidly alerting the crocodile to potential prey near the head. Crocodilians also react rapidly to movement underwater (such as fishes) even when vision is unavailable. Similar pressure receptors, Integumentary Sense Organs (ISOs), are located on the caudal margin of body scales in Crocodylidae and Gavialidae, but not Alligatoridae. Their function is not fully understood, nor is the reason why alligatorids entirely lack them. However, evidence of DPRs exists in extinct crocodyliforms, suggesting their sensory role in water has long been part of their repertoire. Betraying their terrestrial origins, crocodilians are surprisingly mobile predators on land. Although lacking the stamina for pursuit, their explosive force catches most prey unaware. Like all archosaurs, the hind limbs are significantly larger and stronger than the forelimbs, suited to the crocodilian propensity for launching the body forward at speed. Five toes are present on the front feet and four on the back, although residual bones from the fifth still exist. The inner three toes terminate with strong, blunt nails that provide traction; the outer one (back feet) or two (front feet) lack claws and bend backward during walking. There is extensive webbing between the toes on the back feet, but webbing is minimal or absent from the front feet. The limbs are used to crawl, walk, and gallop. The crawl employs the limbs alternately to slide the body across mud, sand, or grass. When sufficiently motivated, the limbs can propel the body forward in a slithering manner at much greater speed, up to 6.2 mph (10 kph). In the uniquely crocodilian high walk, the feet rotate inward toward the body and support it from below. Lifting the head and belly clear of the ground enables the crocodile to traverse obstacles or rough terrain. In a few species, the front and hind limbs move in tandem to gallop. This springlike gait accelerates the crocodile up to 10.6 mph (17 kph) for several seconds until the safety of water can be reached. Cuban crocodiles (C. rhombifer) remind us of the frightening aggression of their terrestrial ancestors when they gallop toward a threat. Water is clearly the crocodilian's preferred domain, a home for prey that live in the water and a magnet for prey that live on land. Mobility is possible through the powerful tail, which makes up half the body's total length. Flattened dorsoventrally to provide extensive surface area for propulsion, the tail is undulated laterally by powerful muscles. Limbs are swept back during rapid swimming, although when moving slowly they help the crocodile steer, brake, reverse, or walk across the bottom. So powerful is the tail that it can drive hundreds of pounds (or kilograms) of crocodile vertically out of the water to capture prey several feet (or meters) overhead. Internally, the pleural cavity contains the lungs, and the visceral cavity houses major organs associated with digestion and reproduction. These cavities are separated by the bilobed liver and diaphragmaticus, a sheet of muscle analogous to the diaphragm in mammals. Inhalation is achieved by contracting the diaphragmaticus,

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which pulls the liver backward and expands the pleural cavity. Thoracic (intercostal) muscles also expand the chest, and reduced pressure in the lungs draws air in through open airways. To exhale, the diaphragmaticus and thoracic muscles relax, compressing the pleural cavity and forcing air out of the airways. Crocodilians control their buoyancy primarily through the volume of air in their lungs. By moving the liver, hind legs, and tail, subtle postural changes are also possible. When diving, air is forced out of the lungs and the crocodilian, which is considerably heavier than water, sinks rapidly. Swimming may facilitate this sinking, and by sweeping the hind legs forward the crocodilian can reverse and submerge simultaneously. Swimming or pushing off the bottom returns the crocodilian to the surface, and positive buoyancy is achieved by filling the lungs with air. Stones called gastroliths in the stomach typically comprise 1–5% of the crocodile's total weight, and their presence may provide additional ballast. Situated between the lungs is the most complex heart in the animal kingdom, apparently the result of adaptation to the demands of the crocodiles' semiaquatic lifestyle and their size. Unlike other reptiles, the crocodilian heart is fully divided into four chambers, as are the hearts of birds and mammals. Uniquely, valves under nervous and hormonal control can alter blood flow. These ensure that vital oxygenated blood circulates between essential areas during oxygen stress, such as while diving, while deoxygenated blood is sent to nonessential areas. During rest and normal exercise, blood in the right ventricle passes via a coglike valve to the pulmonary arteries and lungs to acquire oxygen. During diving, this valve constricts, and deoxygenated blood is diverted to the left aortic arch that leads to the nonessential visceral organs—a pulmonary-to-systemic shunt. Only a small volume is used to collect residual oxygen in the lungs. A second valve, the foramen of Panizza, connects the base of left and right aortic arches. The right aorta directs blood to the head, limbs and tail, and these vital areas require oxygenated blood during oxygen stress. The foramen of Panizza allows oxygenated blood to pass from right to left aortas (to visceral organs) only during rest and normal exercise, cutting them off when not needed. Biochemical adaptations complement the action of the heart. Crocodilian blood contains complex hemoglobin molecules capable of carrying more oxygen molecules than those of any other vertebrate. Crocodilians also endure much higher levels of lactic acid (produced when oxygen is scarce) in their blood than any other vertebrate. Blood pH has been measured below 6.1 without serious consequences, a level that would kill any other vertebrate. The result? A submergence time of nearly two hours when quiescent, even longer under cool conditions. American alligators have remained trapped under ice for eight hours and survived. Heavy activity substantially reduces submergence time, but crocodilians need only to outlast their prey. The blood also houses complex antibacterial proteins capable of fighting off infection. Living in bacteria-filled waters, where injuries from fights are common, a strong immune system is essential. Crocodile blood has even been shown to kill "superbugs" for which scientists have no known cure.

Distribution Crocodilians are found in over 90 countries and islands, generally in tropical and subtropical regions warm enough for successful reproduction. American and Chinese alligators, found in the highest latitudes of any species, do have a limited ability to survive seasonal freezing where deep water or shelter is available. Large adults can even endure being trapped in ice, as long as their internal organs do not freeze and their nostrils project above the surface. Alligatoridae are restricted to North, Central, and South America, except for the Chinese alligator (A. sinensis), which occurs in eastern China. The stronghold of the Crocodylidae is Africa, India, and Asia, although a handful

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are found in the Americas. The single member of Gavialidae is found in India and adjacent countries. Estuarine crocodiles have the widest distribution (India to Vanuatu), although Nile crocodiles cover the greatest area (most of Africa and Madagascar). Spectacled caimans (Caiman crocodilus) number in the millions and are the most numerous throughout Central and South America. Introduced populations of certain species, particularly caimans, are established outside their natural ranges. Crocodilians favor freshwater habitats, although several members of Crocodylidae tolerate higher salinity. Estuarine (also known as saltwater) crocodiles live in freshwater tidal rivers, hypersaline creeks, and along coastlines, and can travel at sea. Their ability to excrete excess salt through lingual salt glands and produce concentrated urine make this possible. All species frequent freshwater and low-salinity areas where available, including tidal rivers, freshwater marshes, and both natural and artificial lakes and pools. Distribution is influenced by the density and diversity of prey, available nesting habitat, shelter for juveniles and adults, thermal conditions, seasonal changes, and competition between species. Temporary range extensions have occurred when competition from one species over another has been reduced due to hunting, etc.

Feeding ecology and diet Crocodilians are renowned for their ability to acquire food, often violently. All species are carnivorous, and mostly generalist. A wide range of mammals, birds, reptiles, amphibians, crustaceans, mollusks, fishes, and insects are taken readily by adults of most species. There are various restrictions, however. Young juveniles are limited to small prey that enter or approach water, primarily insects, spiders, crustaceans, fishes, small reptiles, and amphibians. Juveniles eat regularly, each day if possible. As they grow, the size and range of available prey increases. Species with specialized foraging strategies as adults (such as gharials) begin to exhibit characteristic preferences. Although anything that moves within striking range is often considered fair game for adult crocodilians, most species display some selection criteria. These may include prey availability, but also species-specific preferences influenced by morphology and ecology. Broad-snouted alligatorids with strong bites and blunt teeth include hardshelled prey in their diet; slender-snouted species such as gharials have weaker bites, but their sharp, undifferentiated teeth and slender jaws are ideal for sweeping quickly through water to seize slippery fish. Many Crocodylidae possess jaws between these two extremes, reflecting a generalist diet influenced by prey distribution and seasonal availability. Species with more specialized jaws will, however, take other prey where available. Crocodilians display several hunting techniques. Surprisingly, most prey are small and taken as they approach the head, even in very large adults. The kill zone is an arc traced by the head and neck, although some species literally dive onto prey just below the surface. Terrestrial prey are ambushed at the water's edge, the hunter is either submerged or exposes only the eyes and nostrils. Once within striking range, there is an explosion of teeth and water as the crocodilian propels itself forward using its tail and limbs. Larger prey are dragged into the water where they drown. Although not pack hunters, the presence of several crocodilians in the water speeds a prey's demise. However, capture is not always successful. Misses are common, and large prey bitten on the head, limbs, or body may escape, only to die later from their injuries. Although there are stories of crocodiles using their tails to sweep prey off their feet, hard evidence is sorely lacking, though the tail is important in hunting. Larger crocodiles are often seen using the tail to herd small fish

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into shallow water to be scooped up with a sweep of open jaws. The tail can be used to push the body vertically out of the water, ideal for catching prey flying over the water or hanging in low branches. This behavior has been witnessed in many species. Several species are reported to form a living dam with their bodies, preventing migrating fish from escaping. By cooperating, many individuals increase their chances of success. Nile crocodiles frequently cooperate after large prey is captured, taking turns to hold the carcass while others spins their bodies to rip off mouthfuls of flesh. Crocodilians learn rapidly to associate events with outcomes, often attending predictable events such as prey migrations. Once captured, small prey is deftly manipulated by the jaws for immediate swallowing; head raised, the prey is flicked into the throat under gravity. Larger prey is first crushed several times by the back teeth, perforating skin and shell to assist digestion. Prey too large to be swallowed is typically held firmly in the jaws, then the head is whipped violently to one side. This tears prey apart, and each piece is swallowed once retrieved. Very large prey is first dismembered by holding onto a piece with the jaws, then spinning the body axis several times to twist it off. The carcass is anchored by its own weight, or by other feeding crocodilians. Live prey are easily incapacitated by rolling, as defense against this maneuver is impossible. Once inside the stomach, food is subjected to highly acidic gastric juices. The action of the muscular stomach plus gastrolith stones slowly macerates flesh and renders bone and shell into smaller pieces. Only keratin (found in hair, nails, and turtle shell) is immune. Compacted balls of indigestible material are regularly coughed up. Frequently classed as man-eaters, only a handful of species are considered a significant threat to humans. Most fatalities are reported from American alligators, estuarine crocodiles, and Nile crocodiles, the latter responsible for the greatest number of crocodile-related deaths each year with several hundred people estimated killed or seriously injured. Threats can be reduced significantly by educating people to the danger posed by crocodilians, and providing alternative means of accessing water.

Reproductive biology The basic crocodilian breeding system is polygynous (one male, multiple females), although short-term monogamous pair bonding has been described in Nile crocodiles and possibly other species. Multiple paternity (several males, same female) has also been recorded in some social situations. Once sexual maturity is reached, dictated by size rather than age, reproductive activity follows an annual cycle. Environmental triggers such as changing temperature, rainfall, humidity, and day length trigger hormonal changes in each sex. In males, testosterone levels rise, testes increase in weight, and sperm production increases. In females, estradiol levels rise, triggering the liver to produce vitellogenin for yolk production in the ovaries, and follicle size increases prior to ovulation. Double clutches have been reported in mugger crocodiles (C. palustris) and Nile crocodiles, influenced by extended environmental conditions favorable to breeding. As habitat and climate change geographically, the timing and duration of reproductive activities varies between species and even within a species' distribution. Courtship, mating, and nesting may occur over a period of several months (as in Nile and estuarine crocodiles), or may be concentrated into several weeks (as in American alligators). Johnstone's crocodiles, or Australian freshwater crocodiles (C. johnstonii), nest within a two to three week period, a phenomenon known as "pulse nesting." Crocodilians exhibit two nesting strategies: hole nesting and mound nesting. In the former the female selects a soft substrate, such as sand or mulch, and excavates a chamber several inches deep using her hind legs. After

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laying her eggs, the chamber is concealed again. In mound-nesting species, the female first scrapes material, such as vegetation, soil, or mud, into a mound using her front and hind legs. She also rips up fresh vegetation with her jaws. The resulting mound can be over 3.3 ft (1 m) high and 6.6–9.8 ft (2–3 m) in diameter. Once the mound is complete, the female behaves like a hole nester: she excavates a chamber into the top of the mound with her hind legs, lays her eggs, conceals them, and compacts the nest using her hind legs and body. Only Crocodylidae and Gavialidae excavate hole nests, in those species that nest during the dry season or when little vegetative matter is available. Mound nests are built by Alligatoridae and some Crocodylidae, typically nesting during the wet season or in areas that inundate easily, as the additional height reduces the risk of eggs being drowned by floods. American and Cuban crocodiles have been reported to choose either hole or mound nests, depending on climate and habitat. Nesting location may be determined by available materials, proximity of water, temperature, and even social factors. Females of more territorial species choose solitary nesting sites, isolated visually or by distance from those of other females. Favorite sites may be reused each year, although not necessarily by the same female. More gregarious species may use communal sites. Although under the vigilant watch of several females, there are disadvantages to communal sites. Late nesters may inadvertently dig up older eggs, and predators have an easier time finding eggs where nests are concentrated. Frequency of nesting is also under social pressure. In the wild, between 10% and 80% of females of a given species may nest each year; the percentage determined by the amount of nesting habitat available, the territorial nature of the females, and species-specific differences. As with porcupines, people are curious how crocodilians manage to mate without causing each other grief! In reality, it is a gentle affair (once the competition has been dispensed with, that is). To copulate successfully, males must court females to gain their consent. Males of some species, such as estuarine crocodiles, establish territories that contain a number of females, others, such as American alligators, display competitively to attract females. Courtship may be elaborate or subtle, involving mutual signaling on a visual, olfactory, auditory, and tactile level. Alligators combine rumbling bellows with infrasonic vibrations, the water dancing across their backs proving a potent aphrodisiac for females. Gular musk glands are rubbed across the head and neck in mutual appeasement, and several minutes of head- and tail-raising postures are necessary for consent. Once she consents, the female allows the male to press her underwater. To align his vent with hers, the male rolls the female's body in one direction while rotating his tail in the other, using limbs for purchase. Male crocodilians have a single penis, unlike the hemipenes of most other reptiles. Copulation can last several minutes, and may be repeated over a period of days, although most males attempt copulation with as many females as possible. In captivity, males have been reported copulating with almost 20 females. Copulation may take place in shallow or deep water. After fertilization, eggs are retained in the oviduct for two to four weeks, although periods of six months have been reported in some spectacled caimans. Embryos grow to around 20 somites (cells) before laying, with development believed to resume once eggs are exposed to air. Freshly laid eggs are covered in a fraction of an inch (several millimeters) of mucus, which cushions their impact as they slide into position. Mucus may also prevent gas exchange and hence further development until laying is complete and the mucus dissolves. Clutch size varies greatly: larger species lay up to 70 eggs, smaller ones as few as 10. It can take between 20 and 90 minutes to lay the entire clutch, during which time the female becomes curiously docile. Each egg contains the yolk (nutrient storage), albumen (water supply), leathery inner shell membrane, and hard, calcified outer shell membrane (protection, control of water and gas exchange). The embryo, lying atop the yolk, attaches to the inner

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shell membrane 24 hours after laying. As development continues, an opaque white band spreads around the egg's axis before eventually encompassing the entire egg. Several important variables influence embryo development. Nest temperatures may fluctuate between 84.2°F (29°C) and 93.2°F (34°C), but small changes have significant effects. On average, incubation time lasts 70–90 days, yet higher temperatures reduce this and lower ones increase it. Temperature also determines sex. The phenomenon of temperature-dependent sex determination (TSD) is found in crocodilians, marine turtles, and some lizards. Unlike genetic sex determination (GSD), the sex of the embryo is determined not by sex chromosomes at fertilization, but by a critical temperature-sensitive period during incubation (the middle third). In all crocodilians, the greatest percentage of males is produced around 87.8–89.6°F (31–32°C), with more females produced above and below this temperature. Temperatures above 93.2°F (34°C) and below 84.2°F (29°C) produce almost 100% females, although females produced at higher temperatures suffer higher mortality and genetic deformities. Above 95°F (35°C) and below 80.6°F (27°C) embryos rarely survive. The size of hatchlings, their growth rate, and even preferred basking temperatures are influenced by incubation temperature. All species nest during warm seasonal climates, providing appropriate ambient temperatures for incubation. Solar radiation provides additional heat, although many nests are built in the shade to reduce overheating, and nesting substrate buffers the eggs from extreme temperature fluctuations each day. Mound nests generate heat from the breakdown of plant materials, and even the developing embryos provide some metabolic heat during the later stages of incubation. The smooth-fronted caiman (Paleosuchus trigonatus) typically nests in closed-canopy forests, where ambient temperatures may be insufficient for optimal egg development. To address this, caimans build nests within or adjacent to termite mounds—metabolic heat produced by the termites helps to warm the nest. The female's presence is often required to break open the nest and free the hatchlings. Rainfall helps to cool nests, and some females have been observed urinating on the nest. As a suggested cooling mechanism the volume involved may be insufficient, but it may play a role in chemical marking as hatchlings recognize chemicals in contact with their eggs. Pores permeating inner and outer shell membranes allow gas exchange, and both high humidity and oxygen are necessary for development. Embryo demands increase further as development continues. Development seems highly susceptible to perturbation, yet crocodilian nests provide an effective environment for incubation. But not always. Exposed nests can overheat, and those built in areas prone to flooding are easily submerged. More than 12 hours underwater, particularly later in development when oxygen demands are higher, can spell disaster. Another threat faces developing eggs—nest predators such as monitor lizards, wild pigs, raccoons, even ants. Females of most species defend the nest, often fasting for over two months to remain vigilant, but predators can still catch her off guard. Eventually the demands of the embryo exceed the capability of the egg and hatching occurs. Shortly before emergence, the fully developed embryos may vocalize. Calls propagate from one egg to the next, producing a chorus audible to the adult from 165 ft (50 m) away. The female is typically much closer to the nest, often observed resting her throat directly above the nest chamber close to hatching. The female scrapes back sand, mud, or vegetation from above the eggs with her front legs, and the vibration stimulates the eggs to hatch. Some hatchlings head for water, but others remain and vocalize, often with head raised to encourage the female to carry them in her jaws. By lowering the tongue, a gular pouch is created to hold hatchlings. Some species transport hatchlings one at a time, others, such as Nile crocodiles, transport several. The female carries them to water, opens her mouth, and washes the hatchlings out with a sweeping motion of the head before returning to

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the nest. Hatchlings form small pods or crèches, hiding amongst shoreline vegetation. Not all species perform hatchling transport, and puncture marks caused inadvertently by sharp-toothed females may indicate why not. Infertile or dead eggs are normally eaten by the female, which led to early speculation that females ate their young! In captivity, territorial males of certain species have been observed assisting the female to open nests, hatch eggs, and transport hatchlings. Wild Nile crocodile males occasionally guard juveniles after hatching, but male parental care is atypical. Female protection of juveniles after hatching may last for days (as in Johnstone's crocodiles), weeks (as in Nile crocodiles), or even up to two years (as in American alligators). Hatchlings remain in close proximity to the female, often using her as a convenient basking platform. Vocalization is well developed in crocodilians, and is an important component of juvenile life. Contact calls maintain group cohesion and alert siblings to the presence of food. Distress calls scatter individuals and bring the adult female aggressively to bear. The level of parental care in crocodilians is fascinating. In spectacled caimans, pods from different females may combine into larger crèches tended by resident adults. Even more remarkable, adult females of three species (broad-snouted caimans, Orinoco, and Siamese crocodiles) have been observed feeding juveniles. The female macerates the carcass and juveniles tear off small pieces. This level of parental care is unprecedented for reptiles, and perhaps reminds us of the closer taxonomic affinities between crocodilians and birds.

Conservation status Four of the 23 crocodilian species (Chinese alligator, Orinoco crocodile, Philippine crocodile, Siamese crocodile) are considered Critically Endangered, with a further three (Cuban crocodile, false gharial, Indian gharial) listed as Endangered and considered at risk of extinction. In what is considered the most dramatic recovery of any large vertebrae group, 16 of the 23 species went from Endangered to abundant or not threatened in the last 30 years of the twentieth century. These species' previous decline was attributed primarily to overhunting (for skins) and habitat loss. Recovery was due to a combination of species protection, habitat protection, suppression of illegal trade, and enlightened management programs promoting sustainable use of wild populations as an incentive for their conservation. Efforts to improve the status of the 7 remaining endangered species continue as of 2003.

Resources Books: Alderton, D. Crocodiles and Alligators of the World. New York: Facts on File, 1991. Behler, J. L., and D. A. Behler. Alligators and Crocodiles. Stillwater, MN: Voyager Press, 1998. Campbell, G., and A. L. Winterbotham. Jaws Too: The Natural History of Crocodilians with Emphasis on Sanibel Island's Alligators. Ft. Myers, FL: Sutherland Publishing, 1985. Grigg, G., F. Seebacher, and C. E. Franklin. Crocodilian Biology and Evolution. Sydney: Surrey Beatty and Sons, 2001. Guggisberg, C. A. W. Crocodiles: Their Natural History, Folklore, and Conservation. Harrisburg, PA: Stackpole Books, 1972.

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McIlhenny, E. A. The Alligator's Life History. Boston: Christopher Publishing, 1935. Minton, S. A., Jr., and M. R. Minton. Giant Reptiles. New York: Scribner, 1973. Neill, W. T. The Last of the Ruling Reptiles. New York: Columbia University Press, 1971. Richardson, K., G. J. W. Webb, and S. C. Manolis. Crocodiles: Inside Out. A Guide to the Functional Morphology of Crocodilians. Sydney: Surrey Beatty and Sons, 2002. Ross, C. Crocodiles and Alligators. New York: Facts on File, 1989. Webb, G. J. W., and S. C. Manolis. Crocodiles of Australia. Sydney: Surrey Beatty and Sons, 1989.

Organizations: Crocodile Specialist Group, Florida Museum of Natural History. Box 117800, Gainesville, FL 32611-7800 USA. Phone: (352) 392-1721. Fax: (352) 392-9367. E-mail: [email protected] Web site:

Other: Bibliography of Crocodilian Biology. January 18, 1996 [cited January 2003]. Crocodilians: Natural History and Conservation. December 2002 [cited January 2003]. [Article by: Adam R. C. Britton, PhD]

Any of various tropical American crocodilians of the genus Caiman and related genera, resembling and closely related to the alligators.

[Spanish caimán, from Carib acayuman.]

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Animal Classification: Alligators and caimans Top Home > Library > Animal Life > Animal Classification (Alligatoridae) Class: Reptilia Order: Crocodylia Suborder: Eusuchia Family: Alligatoridae Thumbnail description Powerful animals with a long and muscular tail, four short limbs straddling a scaly body, and strong jaws lined with obvious teeth Size 4–20 ft (1.2–6 m) in total length

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Number of genera, species 4 genera; 8 species Habitat Calm or slow-moving freshwater areas Conservation status Critically Endangered: 1 species; Lower Risk/Conservation Dependent: 1 species Distribution Central to northern South America, parts of southern and western Central America and Mexico, the southeastern United States, and a small area of eastern China

Evolution and systematics Although the order Crocodylia dates back at least 200 million years to the Age of Reptiles, its living members, including those of the family Alligatoridae, can hardly be described as primitive. Instead, they survived the mass extinction 65 million years ago that ended the dinosaurs' reign and evolved over the centuries into animals well suited to their current place in the natural world. Like other members of the order, the family Alligatoridae are the descendants of the Archosauria, or "ruling lizards," which included the dinosaurs. A defining characteristic of these animals is a diapsid skull, which has two temporal openings. Turtles, by comparison, have anapsid skulls with no temporal openings. Within the crocodilians, the family Alligatoridae can be followed as far back as the Paleocene (57–65 million years ago), when caiman ancestors are thought to have roamed the earth. Ancestors of other species, including the American alligator (Alligator mississippiensis) and Chinese alligator (Alligator sinensis), date back to the Miocene and Pleistocene, respectively. The alligatorids are separated into two major groups: the alligators (subfamily Alligatorinae) and the caimans (subfamily Caimaninae). The former group has two living representatives in the Alligator genus. The other six species of alligatorids fall under three genera within the caimans. (Some systematists list only five caimans, with the Yacaré as a subspecies of the common caiman.) In all, the eight species are as follows:

• • • • • • • •

American alligator, Alligator mississippiensis Chinese alligator, A. sinensis common caiman, Caiman crocodilus broad-snouted caiman, C. latirostris Yacaré, C. yacare black caiman, Melanosuchus niger Cuvier's dwarf caiman, Paleosuchus palpebrosus smooth-fronted caiman, P. trigonatus

Physical characteristics In general appearance, alligators are similar to crocodiles, with stout bodies and powerful tails that are at least as long as their bodies. They have long snouts and noticeably toothed upper and lower jaws. Alligatorids are distinguished most notably from the crocodiles by their mandibular teeth, all of which slide inside the upper jaw

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and out of view when the mouth is closed. In contrast, the fourth mandibular teeth in crocodiles are visible outside the closed jaw. Alligatorids are grayish, sometimes tending toward green, brown, yellow, or black, depending on the species. The young are often banded. Adult size ranges from about 4 ft (1.2 m) in Cuvier's dwarf caiman (P. palpebrosus) to 13 ft (4 m) in the American alligator (A. mississippiensis). Like the crocodile's body, the alligatorid body is armored with tough osteoderms and, frequently, large scales that do not overlap. The osteoderms in some species do not extend onto the belly, making this smooth part of the skin highly desirable as leather for human uses. Alligatorids have short legs tipped with claws. The forelimbs are smaller than the hind limbs and have five, rather than four, partially webbed toes. Their body form allows them to glide in a sinuous pattern through the water, normally with just the side-to-side motion of the tail providing the locomotive force. On land the strength of their legs makes them quick and formidable predators.

Distribution Primarily a New World group, all but the two Alligator species occur in southern Mexico, parts of Central America, or northern to central South America. Alligator mississippiensis is the only member of this family to be found in the United States, where it exists in southeastern states, from the Carolinas to Texas. A. sinensis makes its home in eastern China, far distant from its New World relatives.

Habitat Alligatorids are restricted to freshwater areas and frequently are found in lakes, slow-moving streams and rivers, swamps, marshes, and other wetland habitats. Some species even make use of roadside ditches. They prefer sites with slow-moving or still waters. They often inhabit vegetated areas, sometimes with muddy or murky water.

Behavior Alligatorids are ectotherms ("cold-blooded" animals) and most often are seen basking on the shoreline to raise their body temperature. Sometimes they are seen sliding along the shoreline on their bellies, using their feet to push them through the mud and muck to the water. They also do the "high walk," which is somewhat similar to a lizard's walk; alligatorids, however, hold their legs more upright than straddled. Although they may look sedate much of the time, their short legs can give them quick acceleration for grasping a passing mammal. Careful observers also see them floating at the surface of the water, where only their most dorsal surface and occasionally just the nose and the tip of the head are exposed. Often, the animal actually is maintaining its internal temperature through this activity, either lying in the sun-heated upper layers of the water column to warm up or moving to shady, chillier waters to cool off. Their presence is made known when they begin to sweep their tails slowly and propel themselves gracefully forward. While they usually are motionless or swim slowly, they can make quick movements in the water. One noticeable trait is their ability to jettison almost vertically out of the water. This maneuver typically is accompanied by a quick chomp of the jaws around a startled bird or other prey item. Alligatorids, including those in more temperate climates, do not hibernate. While temperatures in the southeastern United States and China can approach freezing in the winter, American and Chinese alligators

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remain active all year, though they are more subdued as temperatures dip and may even become dormant. To beat the cold, they move to shallow water and lie motionless, with just the nose poking into the cold air. Young alligators, on the other hand, may retreat to the mother's den to survive cold snaps. Juveniles and adults make use of burrows during winter months. Alligatorids often live in groups and form dominance hierarchies, at least during the breeding season and sometimes all year. The highest-ranking individuals exert their dominance through various ritualized behaviors, which may include slaps of the head against the surface of the water, loud vocalizations, and open-mouthed charges.

Feeding ecology and diet A typical juvenile diet includes snails and other invertebrates, whereas adults of various species commonly eat fish, small mammals, other reptiles (including smaller alligatorids), or birds. Opportunistic feeders, alligatorids continue to eat clams, snails, and invertebrates into adulthood. The larger species, including the black caiman, are known to take large prey, such as small deer and cattle. Predation of alligatorids occurs primarily among eggs and hatchlings. Raccoons, coati, skunks, foxes, and other mammals, as well as snakes and various raptors, are known to raid nests or snatch up young alligatorids. Once an alligatorid reaches about 3 ft (1 m) in length, the risk of predation decreases. Nonetheless, anacondas in South America occasionally kill adult caimans, and alligatorids have been reported to have cannibalistic tendencies. Cannibalism is rare, however, and alligatorids frequently live peacefully in large groups.

Reproductive biology Alligatorids begin the reproductive season in the spring. Following courtship, which may include loud bellows, tactile types of behavior, and underwater vibrations of the male's trunk, alligatorids use vegetation to construct nest mounds, where they lay from one dozen to five dozen eggs, depending on the species. Egg laying generally takes place once a year, in midsummer, with hatching one to two months later. Female alligatorids typically respond to sounds emanating from the neonate, dig up the nest, and assist in their hatching. Temperaturedependent sex determination has been associated with several species, including the American alligator and common caimans. Low nest temperatures (below 88°F, or 31°C) produce female hatchlings, and high temperatures (above 90°F, or 32°C) produce males.

Conservation status The Chinese alligator is listed by the IUCN Red Book as Critically Endangered. This status stems primarily from loss of habitat due to human encroachment. According to the IUCN Crocodile Specialist Group, "The Chinese alligator is the most critically endangered crocodilian in the world. Thousands are bred in captivity, but fewer than 150 remain in the wild." The group is working with the Chinese government to protect the species and has launched the Chinese Alligator Fund to assist in these efforts. In addition, many conservation efforts over the past three decades have been implemented to prevent overharvesting of other alligatorids. The only other species listed by the IUCN is the black caiman, which is listed as Lower Risk/Conservation Dependent.

Significance to humans 24

Although the benefit is difficult to quantify, some species of alligatorids play an important role in the tourism industry. American alligators in the southeastern United States, for example, have become tourist attractions, drawing visitors to the Everglades of southern Florida and the bayous of Louisiana. Several members of this family are hunted, especially for their skin, which is used as leather for shoes, bags, and various accessories. Humans also hunt these animals for meat and, recently, for their gonads, which are used to make perfume.

Species accounts American alligator Chinese alligator Common caiman Smooth-fronted caiman

Resources Books: Alderton, D. Crocodiles and Alligators of the World. New York: Facts on File, 1991. Ashton, Ray E., and Patricia Sawyer Ashton. Handbook of Reptiles and Amphibians of Florida. Part 2: Lizards, Turtles and Crocodilians. 2nd edition. Miami: Windward Publishing Co., 1991. Behler, J. L., and D. A. Behler. Alligators and Crocodiles. Stillwater, MN: Voyager Press, 1998. Campbell, G., and A. L. Winterbotham. Jaws Too: The Natural History of Crocodilians with Emphasis on Sanibel Island's Alligators. Ft. Myers, FL: Sutherland Publishing, 1985. Guggisberg, C. A. W. Crocodiles: Their Natural History, Folklore, and Conservation. Harrisburg, PA: Stackpole Books, 1972. Hirschhorn, Howard H. Crocodilians of Florida and the Tropical Americas. Miami: Phoenix Publishing Co., 1986. King, F. Wayne, and Russell L. Burke, eds. Crocodilian, Tuatara and Turtle Species of the World: A Taxonomic and Geographic Reference. Washington, DC: Association of Systematics Collections, 1989. McIlhenny, E. A. The Alligator's Life History. Boston: Christopher Publishing, 1935. Minton, S. A., Jr., and M. R. Minton. Giant Reptiles. New York: Scribner, 1973. Neill, W. T. The Last of the Ruling Reptiles. New York: Columbia University Press, 1971. Ross, Charles A., ed. Crocodiles and Alligators. New York: Facts of File, Inc., 1989. Zug, George R, Laurie J. Vitt, and Janalee P. Caldwell. Herpetology: An Introductory Biology of Amphibians and Reptiles. 2nd edition. San Diego: Academic Press, Inc., 2001.

Periodicals: 25

Brazaitis, P., M. Watanabe, and G. Amato. "The Caiman Trade." Scientific American 278 (March 1998): 70–76. Stewart, D. "Visiting the Heart of Alligator Country." National Wildlife 38, no. 4 (June/July 2000): 20–27. Thorbjarnarson, J. "The Hunt for Black Caiman." International Wildlife 29 no. 4 (July/August 1999): 12–19. Thorbjarnarson, J., X. Wang, and L. He. "Reproductive Ecology of the Chinese Alligator (Alligator sinensis) and Implications for Conservation." Journal of Herpetology 35, no. 4 (December 2001): 553–558. Zimmer, C. "Prepared for the Past." Natural History 110, no. 3 (April 2001): 28–29.

Organizations: Crocodile Specialist Group, Florida Museum of Natural History. Box 117800, Gainesville, FL 32611-7800 USA. Phone: (352) 392-1721. Fax: (352) 392-9367. E-mail: [email protected] Web site:

Other: Animal Diversity Web. [cited December 2002]. "Crocodilian Species List." 2002 [cited December 2002]. "Alligatoridae." The Reptipage. August 2002 [cited December 2002]. "Alligatoridae: Alligators, Caimans, and Their Prehistoric Relatives." December 1999 [cited December 2002]. "Crocodilian Biology Database." August 2002 [cited December 2002]. [Article by: Leslie Ann Mertz, PhD]

Britannica Concise Encyclopedia: caiman Top Home > Library > Miscellaneous > Britannica Concise Encyclopedia

Any member of several species of Central and South American reptiles of the alligator family. Like the rest of the crocodile order, caimans are amphibious, lizardlike carnivores. They live along the edges of rivers and other bodies of water, and reproduce by laying hard-shelled eggs in nests built and guarded by the female. The largest species is the black caiman (Melanosuchus niger), a potentially dangerous animal with a maximum length of about 15 ft (4.5 m). Average lengths for the other species (genera Caiman and Paleosuchus) are 4 – 7 ft (1.2 – 2.1 m). 26

For more information on caiman, visit Britannica.com.

Veterinary Dictionary: caiman Top Home > Library > Animal Life > Veterinary Dictionary Crocodilian reptile of the family Alligatoridae, very similar to alligators; resident in Central and South America. Genus name is Caiman, e.g. C. sclerops the spectacled caiman.

Wikipedia: Alligatoridae Top Home > Library > Miscellaneous > Wikipedia Alligators and Caimans Fossil range: Cretaceous Recent

American Alligator

Scientific classification

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Kingdo m: Animali a

Phylum: Chordat a

Class: Saurops ida

Order: Crocodil ia

Family: Alligat oridae Gray, 1844

Living Genera Alligator Caiman Melanosuchus Paleosuchus

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Alligators and caimans are archosaurs, species of crocodilians and form the family Alligatoridae (sometimes regarded instead as the subfamily Alligatorinae).

Contents [hide]

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1 Differences from crocodiles 2 True alligators 3 Caimans 4 Species

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5 References

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Differences from crocodiles Alligators differ from crocodiles principally in having wider and shorter heads, with more obtuse snouts; in having the fourth, enlarged tooth of the under jaw received, not into an external notch, but into a pit formed for it within the upper one; in lacking a jagged fringe which appears on the hind legs and feet of the crocodile; in having the toes of the hind feet webbed not more than half way to the tips; and an intolerance to salinity, alligators strongly preferring fresh water, while crocodiles can tolerate salt water due to specialized glands for filtering out salt. In general, crocodiles tend to be more dangerous to humans than alligators.

True alligators Alligators proper occur in the fluvial deposits of the age of the Upper Chalk in Europe, where they did not die out until the Pliocene age. The true alligators are now restricted to two species, A. mississippiensis in the southeastern United States, which can grow to 4.24 m (14 ft) and weigh 1000 lbs (454.5 kg)[1], with the record length of 5.81 m (19 ft 2 in), and the small A. sinensis in the Yangtze River, People's Republic of China, which grows to an average of 1.5 m (5 ft). Their name derives from the Spanish el lagarto, which means "the lizard".

Alligator prenasalis fossil

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Caimans In Central and South America, the alligator family is represented by five species of the genus Caiman, which differs from the alligator by the absence of a bony septum between the nostrils, and the ventral armour is composed of overlapping bony scutes, each of which is formed of two parts united by a suture. Some authorities further divide this genus into three, splitting off the smooth-fronted caimans into a genus Paleosuchus and the Black Caiman into Melanosuchus. Caimans tend to be more agile and crocodile-like in their movements, and have longer, sharper teeth than alligators.[2] C. crocodilus, the Spectacled Caiman, has the widest distribution, from southern Mexico to the northern half of Argentina, and grows to a modest size of about 2.2 meters. The largest is the near-threatened Melanosuchus niger, the Jacare-assu, Large, or Black Caiman of the Amazon. Black Caimans grow to 16.5 feet (5 meters) [3], with the largest recorded size 5.79 m (19 ft). The Black Caiman and American Alligator are the only members of the alligator family posing the same danger to humans as the larger species of the crocodile family. Although the Caiman has not been studied in-depth, it has been discovered that their mating cycles (previously thought to be spontaneous or year-round) are linked to the rainfall cycles and the river levels in order to increase their offspring's chances of survival.

Species

An alligator nest at Everglades National Park, Florida, United States. •

ORDER Crocodilia o Family Alligatoridae  Genus Leidyosuchus (extinct)  Genus Deinosuchus (extinct)  Subfamily Alligatorinae  Genus Albertochampsa (extinct)  Genus Chrysochampsa (extinct)  Genus Hassiacosuchus (extinct)  Genus Navahosuchus (extinct)  Genus Ceratosuchus (extinct)  Genus Allognathosuchus (extinct)  Genus Hispanochampsa (extinct)  Genus Arambourgia (extinct) 30

Genus Procaimanoidea (extinct) Genus Wannaganosuchus (extinct) Genus Alligator  Alligator prenasalis (extinct)  Alligator mcgrewi (extinct)  Alligator olseni (extinct)  Chinese Alligator, Alligator sinensis  Alligator mefferdi (extinct)  American Alligator, Alligator mississippiensis Subfamily Caimaninae  Genus Necrosuchus (extinct)  Genus Eocaiman (extinct)  Genus Paleosuchus  Cuvier's Dwarf Caiman, Paleosuchus palpebrosus  Smooth-fronted Caiman, Paleosuchus trigonatus  Genus Purussaurus (extinct)  Genus Mourasuchus (extinct)  Genus Orthogenysuchus (extinct)  Genus Caiman  Yacare Caiman, Caiman yacare  Spectacled Caiman, Caiman crocodilus  Rio Apaporis Caiman, C. c. apaporiensis  Brown Caiman, C. c. fuscus  Caiman lutescans (extinct)  Caiman sorontans[citation needed] (extinct) - Not reported in the literature, probably a 'nomen nudum'  Broad-snouted Caiman, Caiman latirostris  Genus Melanosuchus  Melanosuchus fisheri (extinct)  Black Caiman, Melanosuchus niger   



References 1. ^ 2. ^ Guggisberg, C.A.W. (1972). Crocodiles: Their Natural History, Folklore, and Conservation, pp.195. ISBN 0715352725. 3. ^

Melanosuchus niger (SPIX, 1825) NAMES | DISTRIBUTION | HABITAT | STATUS | APPEARANCE | IMAGES | DIET | BREEDING | CONSERVATION

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FAMILY: ALLIGATORIDAE

A. mississippiensis

COMMON NAMES:

Black caiman, Caimán, Caimán negro, Caïman noir, Lagarto negro, Jacare Açu, Jacaré Assú, Jacare Açu, Jacare Uassu, Jaracé Una, Yacare Assu

A. sinensis C. crocodilus

NAME ETYMOLOGY:

C. c. apaporiensis

> Melanosuchus means "black crocodile", derived from melas (Greek genitive for "black") +

C. c. fuscus

soukhos (Greek for "crocodile", leading to the Latin suchus)

C. latirostris

> niger means "black" (Latin), referring to the very dark colouration of this species

C. yacare M. niger

DISTRIBUTION:

P. palpebrosus

[CLICK ON MAP FOR DETAILED RANGE]

P. trigonatus

Bolivia, Brazil, Colombia, Ecuador, French Guiana, Guyana, Peru, Venezuela (unconfirmed)

FAMILY:

HABITAT:

CROCODYLIDAE

Found in various freshwater habitats (e.g. slow-moving C. acutus

rivers, streams, lakes and flooded savannah and

C. cataphractus

wetlands). Although overlapping with the range of other caiman species in South America, it

C. intermedius

appears to occupy different habitat niches.

C. johnstoni C. mindorensis C. moreletii

STATUS:

C. niloticus

CITES: Appendix I

C. novaeguineae

IUCN Red List: LRcd (LOW RISK, CONSERVATION DEPENDENT)

C. palustris

Estimated wild population: 25,000 to 50,000

C. porosus

Summary: Widely distributed, but historically heavily exploited. Most populations

C. rhombifer

appear to be recovering well.

C. siamensis O. tetraspis

APPEARANCE:

T. schlegelii

[click on image for enlargement]

Largest species in the family Alligatoridae (males can reach at least 4 metres, FAMILY:

and huge 6 metre caimans have been reported but not confirmed). General

GAVIALIDAE

appearance not dissimilar to Alligator mississippiensis. As the common name suggests, they have a dark colouration. The lower jaw has grey banding (brown in older

G. gangeticus

animals), and pale yellow or white bands are present across the flanks of the body, although these are more prominent in juveniles. This banding fades only gradually as the animal

DICHOTOMOUS KEY [German]

MAIN MENU

matures. Structurally dissimilar to other caiman species, particularly in the shape of the skull. Has distinctly larger eyes, and a relatively narrow snout. The bony ridge extending from above the eyes down the snout, as seen in other caiman, is present.

DENTITION:

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5 pre-maxillary; 13-14 maxillary; 18-19 mandibular Total no. of teeth = 72-76

IMAGES: [click on image for enlargement]

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Head portrait of juvenile

Juvenile held in hand

Juveniles in a holding container

Juvenile's disruptive camouflag e patterns

Adult black caiman floating in water

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NAMES | DISTRIBUTION | HABITAT | STATUS | APPEARANCE | IMAGES | DIET | BREEDING | CONSERVATION

Crocodylus acutus (CUVIER, 1807) NAMES | DISTRIBUTION | HABITAT | STATUS | APPEARANCE | IMAGES | DIET | BREEDING | CONSERVATION

FAMILY: ALLIGATORIDAE

A. mississippiensis A. sinensis

COMMON NAMES:

American crocodile, Cocodrilo americano, Crocodile d'Amérique, Caimán de Aguja, Central American alligator, Cocodrilo de Rio, Crocodile à museau pointu, Lagarto Amarillo, Lagarto Real, Llaman Caimán, South American alligator, American saltwater crocodile

C. crocodilus C. c. apaporiensis

NAME ETYMOLOGY:

C. c. fuscus

> Crocodylus is derived from the Greek krokodeilos which means literally "pebble worm"

C. latirostris

(kroko = pebble; deilos = worm, or man) referring to the appearance of a crocodile.

C. yacare

> acutus means "sharp" or "pointed" (Latin), referring to the shape of the snout

M. niger P. palpebrosus

DISTRIBUTION:

P. trigonatus

[CLICK ON MAP FOR DETAILED RANGE]

Southern United States, Central and South America: FAMILY:

Belize, Cayman Islands (Extinct), Colombia, Costa

CROCODYLIDAE

Rica, Cuba, Dominican Republic, Ecuador, El Salvador, Guatemala, Haiti, Hispaniola, Honduras, Jamaica,

C. acutus

Margarita (poss.), Martinique (poss.), Mexico,

C. cataphractus

Nicaragua, Panama, Peru, Trinidad (poss.), United

C. intermedius

States (extreme south Florida), Venezuela

C. johnstoni C. mindorensis

HABITAT:

C. moreletii

Both freshwater (including river, lakes and reservoirs) and brackish coastal habitats (including

C. niloticus

tidal estuaries, coastal lagoons and mangrove swamps). A large population is present in Lago

C. novaeguineae

Enriquillo (Dominican Republic), a landlocked hyper-saline lake. Crocodiles in these

C. palustris

conditions osmoregulate primarily by drinking available freshwater. Possibly the most unusual

C. porosus

location is a population which occupies the brackish water cooling canals at the Turkey Point

C. rhombifer

nuclear power plant in Florida. This species also constructs long burrows for aestivation and

C. siamensis

as a retreat from adverse conditions. Considerable overland distances can also be travelled

O. tetraspis

in search of new habitats.

T. schlegelii

STATUS: FAMILY:

CITES: Appendix I

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GAVIALIDAE

IUCN Red List: VU A1ac (VULNERABLE) Estimated wild population: 10,000 to 20,000

G. gangeticus

Summary: Gradually recovering in the US, but relatively poor survey data in Central and South America indicate some populations stable but others declining.

DICHOTOMOUS KEY [German]

APPEARANCE: [click on image for enlargement]

MAIN MENU

One of the larger crocodilian species. Males typically reach 5 metres, with reports of 6 and even 7 metre animals (unconfirmed). Dorsal armour is irregular and much reduced in comparison with other species. There is a distinctive swelling in front of each eye, visible in all except the hatchlings. Juveniles are lighter coloured (light tan) than more mature animals, with banding on the body and tail. Adults take on an olive brown colour. Iris is silvery.

DENTITION: 5 pre-maxillary; 13-15 maxillary; 15 mandibular Total no. of teeth = 66-68

IMAGES: [click on image for enlargement]

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Adult crocodile viewed from the front

Postoccipital and nuchal scales

Teeth erupting through upper jaw

DIET: Primarily fish, and other aquatic species including turtles and crabs. Also takes birds. Feeds primarily at night. Juveniles take small fish and invertebrates. Often blamed for the disappearance of domestic animals in more populated areas. Occasional reports of attacks on humans, but authenticated records are very rare.

BREEDING: Females reach sexual maturity at lengths of 2.5 m. Populations adapt their breeding strategy to suit the environment. This species is mainly a hole nester, but populations without access to suitable nest sites which can be excavated (relatively well drained) will build mound nests using whatever nesting materials are available. Flooding creates high mortality. Nesting occurs during the dry season (to minimise flooding, especially in hole nests which are in danger of falling below the water table after heavy rains), following an extended courtship

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period which can last up to two months. The minimum number of eggs laid in the nest can be around 20 in some populations, but is usually between 30 and 60, the mean being around 38. Nests are often found which contain eggs from two separate females. Hatching, after around 90 days, coincides with the beginning of the annual rains. At hatching, juveniles are around 25 cm in length. The degree of parental care seems to be variable, with some sources noting minimal protection of the nest and the newly hatched juveniles, while others report a higher degree of parental attention, from guarding the nest (a burrow is constructed nearby), to assisting the hatching juveniles and subsequently protecting them (predators include birds, wild cats, raccoons and even large fish). However, it appears that the juveniles move away from the nesting area within a few days of hatching. They have been noted to vocalise less than other species during the first few weeks of life. It has been suggested that this lack of parental care and early juvenile dispersal is a direct result of the high hunting pressures that the species was subjected to in the second quarter of the century - a rapid adaptation to survive.

CONSERVATION: Decline in numbers was primarily due to demand for the high-quality skin of this species, mainly from 1930 to 1960 - and it is perhaps ironic that this high-value skin now makes sustainable use management programs feasible. Presently, continuing hunting (on a lesser scale) combined with habitat destruction (e.g. destruction of coastal mangrove habitat in Ecuador for aquaculture) are the most immediate threats. In Nicaragua, for example, illegal hunting occurs during the legal harvesting of caimans. Although information on population and behavioural ecology is well documented, inadequate survey data are available except in the United States. Current studies will hopefully improve this situation. Presently, it appears that while the species has the most wide-ranging distribution of any New World crocodile, it is depleted to a 'significant' extent over most of its range, particularly so over almost a third of this. In a few areas, populations are considered to be relatively healthy (e.g. Belize and Cuba). C. acutus is completely protected in most countries where it occurs, but the enforcement of this protection is often inadequate although management programs exist in 8 countries within its range, legislation is ineffective or simply not acted upon. In addition, it can be difficult to distinguish the skin from other crocodilian species, making enforcement more difficult. Other measures include farming and ranching in a small number of countries. This is likely to expand (e.g. Colombia, Jamaica), although the status of wild populations from which stock would no-doubt be taken must be carefully monitored, once basic survey data have been compiled. A percentage of farmed stock should be incorporated into a reintroduction program (this strategy is necessary in Cuba to assist the recovery of wild populations, as farming has been successful). In other areas (e.g. Venezuela), much crocodile habitat exists, but there are few crocodiles remaining. A restocking program would help to ensure the continued survival of these populations. Successful programs include a population of C. acutus at Lago Enriquillo in the Dominican Republic, which has a stable population of around 200 animals, together with a genetic reserve of growing juveniles in captivity. In the US, the Fish and Wildlife service formulated a

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recovery plan in 1984 for this species, centering around habitat protection and management, regular population surveys, reduction in mortality (increased education, plus other measures such as road crossing culverts) and the consideration of captive propagation. Major threats in the US are from habitat removal (e.g. mangrove swamps outside the Everglades National Park) and direct human disturbance (e.g. shooting, road-kills, gill-net fishing, vandalism and other disturbance of nests) which, although low, may be higher than the recruitment rate of the remaining crocodile population. In 1993, 34 nests were recorded in Florida, and the number is steadily growing.

MORE INFORMATION: For more information on distribution and conservation issues for this species,see the CSG Action Plan resource.

SIGNIFICANT REFERENCES: Campbell, HW (1972). Ecological or physiological interpretations of crocodilian nesting habits. Nature 238: 404-405 Departamento de Vida Silvestre (1993). Estudio y Protecion del Cocodrilo Americano (Crocodylus acutus) en la Republica Dominicana. Secretaria de Estado de Agricultura, Santo Domingo, Dominican Republic. 209 pp. Kushlan, JA & Mazotti, F (1989). Historic and present distribution of the American crocodile in Florida. J. Herpetol. 23(1): 1-7 Kushlan, JA & Mazotti, F (1989). Population biology of the American crocodile. J. Herpetol. 23(1): 7-21 Medem, F (1981). Los Crocodylia de Sur America. Vol. 1. Los Crocodylia de Colombia. Colciencias, Bogota. 354 pp. Moler, P & Abercrombie, C (1992). Growth and survival of Crocodylus acutus in South Florida, USA. In: Crocodiles. Proceedings of the 11th Working Meeting of the Crocodile Specialist Group. IUCN, Gland, Switzerland. p.14 Schubert, A (1994). Conservation of American crocodile. Crocodile Specialist Group Newsletter 13(3): 14 Thorbjarnarson, J (1989). Ecology of the American crocodile, Crocodylus acutus. In: Crocodiles. Their Ecology, Management and Conservation. A Special Publication of the Crocodile Specialist Group. IUCN, Gland, Switzerland. pp. 228-258 NAMES | DISTRIBUTION | HABITAT | STATUS | APPEARANCE | IMAGES | DIET | BREEDING | CONSERVATION

Crocodiles in Costa Rica (FINAL PAPER) This topic submitted by Elizabeth Nellums ( [email protected]) at 1:06 PM on 5/17/03. 39

The class gets ready to board Bahamas Air on San Salvador, Bahamas. See other beautiful phenomena from the Bahamas.

Tropical Field Courses -Western Program-Miami University

I. Introduction II. Evolutionary history of crocodiles III. Physical and physiological characteristics IV. Descriptions of behavior and psychology V. Life cycle of crocodiles VI. Crocodilian habitat requirements VII. History of crocodilian exploitation VIII. The Costa Rican population IX. Global outlook for crocodiles X. Recommendations I. Crocodilians are a large family with a long history dating back to the Mesozoic. There are several subtypes of crocodilians, including crocodiles, caimans, and alligators. There are no alligators in Costa Rica, but there are several species of caiman, particularly the Spectacled Caiman (Caiman crocodilus) but also the brown or American Caiman, (Caiman crocodilus fuscus), a subspecies of C. crocodylus. This paper focuses solely on the crocodiles, of family Crocodylidae and subfamily Crocodylinae. (Kricher, 2002) This grouping includes Old World Nile Crocodiles (C. niliticus), and the Indo-Pacific Crocodile (C. porosus). In the Neotropics, of the American crocodile (C. acutus), the MoreletÕs crocodile (C. moreletii) the Orincono crocodile (C. intermedius), and the Cuban crocodile (C. rhombifer), only the American crocodile is found in Costa Rica. Therefore most of this paper is focused on C. actutus. The nomenclature comes from the Greek krokodeilos which is translated as "pebble worm" (kroko = pebble; deilos = worm, also man) and refers to the elongated crocodile shape. Acutus means "sharp" or "pointed" in Latin and is probably describing the shape of the snout. (Britton, 2002) It is a large species but not the largest, is aggressive but not notably so, and has a large range. It is found in Belize, Colombia, Costa Rica, Cuba, Dominican Republic, Ecuador, El Salvador, Guatemala, Haiti, Honduras, Jamaica, Nicaragua, Mexico, Panama, Peru, Venezuela and the United States, (Britton, 2002) - a small population exists in southern Florida. Crocodiles have only recently come to prominence as an important species worthy or preservation; they have

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been widely hunted as a threat to humans and livestock, and killed for their skins. But toay crocodiles are an identified Òkeystone species,Ó meaning one that maintains ecosystem structure and function by their activities. (Ross, J. 2000) They are known for selective predation on fish species, recycling nutrients, and maintenance of wet areas in droughts by digging holes or burrows during dry periods. In this paper we will examine several aspects of the Costa Rican crocodile, including its genealogy, physiology, behavior, life cycle, history, and future prospects. II. Crocodilian history is relatively well-known because their marshy habitats favor fossilization. They are the only living relatives of a large and ancient group of reptiles, the Archosauria, (Òruling reptiles,Ó) which also contained dinosaurs. They dominated the planet during the Mesozoic era, 245- 265 million years ago. (Ross, 1989) During this period some of their relatives reached 50 meters in length. The Archosauria was comprised of dinosaurs, pterosaurs, and the thecodontians, which may have been the precursor to modern crocodiles. This name describes the setting of teeth in the animals; thecodont teeth are set into the jaw sockets rather than fused to other sides of the jaw as is typical in other reptiles. (Ross, 1989) The earliest crocodilians and their immediate precursors existed 215 million years ago and were probably terrestrial predators, with long slender limbs and well-developed body armor. Only later did they become amphibious; in fact, they were probably fast runners. These animals, called protosuchian (suchia is a common ending of words relating to crocodiles, coming from the latin of Sobek, a crocodile god of ancient Egypt) (Ross, 1989) were hardly more than 1 meter long with a short snout. The earliest known crocodilianÐlike reptiles among the archosaurs are the sphenosuchians, found in rocks dating to the late Triassic (230 mya) (Ross, 1989) and the oldest known true crocodiles are 200 million years old. These sphenosuchians were found in Europe, South America and South Africa (Ross, 1989); in fact, the genus Crocodylus was found all over the world in the tertiary period. The mesosuchians, intermediate crocodilian ancestors, were much more diverse than modern eusuchians. They seem to have retreated to the equator just before the Cretacious (65 mya) which may explain how they escaped the famous K-T mass extinction of that period. The crocodiles that we know today appeared right around this period some 80 million years ago, (Ross, 1989) and have since been restricted to mainly warm or temperate regions. However, crocodilians survived in Europe until less than 5 mya. They seem to have had limited success and diversity there due to the modern cooling climate. (Ross, 1989) Because it is known that they existed in the Cretacious, the crodocile's design plan has lasted about 200 million years; few changes have affected the modern crocodile since then. (Ross, 1989) The evolutionary history of modern extant crocodiles is fairly obscure, but they probably evolved originated in Eurasia. (Alderton, 1998) Speaking of C. acutus specifically, it is likely to have evolved fairly recently, because it is mostly absent from the fossil record. Scientists believe that it probably evolved in the Caribbean and migrated to its current range. (Alderton, 1998) III. Today crocodilians are the most advanced of all reptiles. They have a unique combination of reptilian and mammalian/avian characteristics Ð in fact, they are more closely related to birds than lizards. (Ross, 1989) They have a bird-like brain but no bladder and a reptilian digestive system. (Ross, 1989) Like the birds, crocodiles have an elongate outer-ear canal, a muscular gizzard, and complete separation of the ventricles of the heart. They are called advanced because of their four-chambered heart, reptile diaphragm, and cerebral cortex. (Ross, 1989) The American crocodile is a relatively large species, with males having maximum lengths of 5Ð6 meter range, although some 7 meter individuals have been reported. (Britton, 2002) It is two-thirds as heavy as and American

41

Alligator of the same length, and therefore moves more quickly. (Ross, 1989) Dorsal armor is irregular and much reduced in comparison with other species, and in front of each eye is a distinctive swelling. Skin is formed from a thick dermal layer covered with non-overlapping epidermal scales. The surface scales of each scute sloughs off individually rather than shedding in large patches. Adults are olive brown all over, while the lighter-colored juveniles are tan with banding on the body and tail. The American crocodile also possesses a distinctive silvery iris. Like all crocodiles, the snout is pointed rather than rounded as it in Alligators, and the fourth tooth is visible when the jaws are closed - the same tooth of an alligator (both have this extra-long tooth) fits into the upper jaw. Crocodilians have strong muscles that allow the jaws to snap shut with incredible force Ð they are capable of crushing bones, skulls, and cast iron. However, the muscles for opening the jaw are relatively weak, which allows even a rubber band to keep the jaws of smaller crocodiles closed. This explains the trick of `gator wrestling. The teeth are conical in shape and anchored to the sockets by connective tissue, and in C. acutus there are between 66 and 68 individual teeth. (Britton, 2002)They fall out throughout the lifespan and are replaced in alternate rows along the jaw. (Alderton, 1998) Crocodiles have no lips, meaning that they cannot close their mouths underwater. They are prevented from ingesting water, however, by a secondary palate which blocks the throat Ð the region inside the mouth is actually still external to the body. Both salt and freshwater Ð crocodiles, unlike alligators, have maintained salt glands on the tongue, even those that do not have contact with salt water, probably a holdover from their marine ancestry. (Alderton, 1998) The brain is small but complex, and the senses are well adapted. They have an excellent sense of smell and a fine ability to hear, as evidenced by the complex vocalizations of crocodilian species. External ear openings are covered with a flap to protect the inner ear during diving. (Ross, 1989) Both the eyes and nostrils are high on the head, so that they are above the water when the crocodile swims. The eyes are typically vertebrate, with a vertical pupil and a reflective layer behind the retina. They have moveable eyelids and a third transparent eyelid called a nicitating membrane. They apparently posses color vision but they cannot focus under water, which indicates that they use other senses when submerged. (Ross, 1989) They are highly evolved predators, highly motile and metabolically efficient. They have fast reflexes and effective locomotor ability on land, where they walk on erect legs, and in the water, where they use the long, powerful tail to swim. They move by lateral S-shaped undulations of the tail with limbs held close to the body. (Ross, J. 2000) On land they posses two distinct types of walk: the splayed low-belly sprawl of lizards, and the more mammalian Òhigh walkÓ employed for in fast travel on land. The reason for this is the unusual ankle structure that they share with the early thecodontians, unique from other reptiles. (Ross, 1989) Their feet have unusual flexibility so the can support the crocs in various positions. They have five toes on the front feet and four on the back, all of which are partially webbed to aid in swimming. Their body systems are well adapted to the marine environment, where they attempt to maintain their body temperature within narrow limits by basking in the sun when cool and seeking shade or water when hot. (Ross, J. 2000) Like all reptiles they are ectotherms, and do not regulate their body temperature internally. However, the circulatory system can divert blood away from the peripheral systems during dives or to reduce heat loss. They have well-evolved metabolisms that use and store nearly the entirety of a meal. Because of this they ingest no more than 50 full meals a year (Ross, 1989) and a large crocodile can last a year without eating. Newly hatched crocodiles do not need to eat for four months, surviving on the stored fat from the yolk Ð in fact, 60 percent of the fat in crocodile diets is stored. The tradeoff for this efficient system is a low oxygen count in the blood (it can also impair growth.) Crocodiles recover slowly from exercise and are easily exhausted, and have high levels of lactic acid in the blood Ð however, they can also survive a blood acidity that would kill most other animals. (Ross, 1989) They are, however, excellent and adaptive hunters, with an ability to consume and digest almost everything they encounter. The stomach is the most acidic of any vertebrate. (Ross, 1989) Hatchlings eat mostly insects while juveniles eat fish, frogs, tutles, small mammals, and invertebrates.

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Larger crocodiles also eat larger mammals and birds, as well as up to 70% fish. Crocodilian snouts are related to their diets Ð narrow-snouted animals tend to favor fish, and a crocodileÕs narrow snout reflects this tendency towards almost any fish they encounter. IV. Crocodilians have complex behaviors including social interactions, communication, dominance hierarchies, and coordinated feeding. Socially, crocodiles have uniquely complicated lives, related more closely to birds and mammals than to other reptiles. They have a complex system of communication. It is apparent that crocodiles recognize each other and respond accordingly. Physical, vocal, and chemical factors probably all play a part, not all of which is completely understood. Chemosensory signals, for example, are widely suspected but little studied. It is likely that crocodiles, with a keen sense of smell, rely on musk for recognition and mating cues. There is much more that needs to be known in this area, but physical signals are widely reported and well understood, especially in connection with vocal and auditory clues. For example, many crocodilians are known to head-slap the water to assert dominance, snap their jaws in the water to produce a popping sound, and blow bubbles. (Ross, 1989) Tail thrashing should be interpreted as a threat and often precedes an offensive charge. Many of these cues indicate the arrival or presence of the speaker, but they are also used to attract attention or to indicate aggression. Another well-known communication, especially in American crocodiles, is the raising of the head, called snout lifting. This is a submissive signal used during courtship, mating, or between a dominant and subordinate male. In C. acutus it is used almost exclusively by females during daily social interactions. It probably conveys information about the individualÕs sex. The exposure of the vulnerable underside of the throat is interpretated by researchers as a symbol of Ògood intentions.Ó Vocally, American crocodiles do not lead the crocodilian pack. Alligators are especially vocal and are known to bellow for extended periods, and among crocodilians there are distinct and well-documented calls for a variety of purposes, including aggression, seduction, dominance, and distress. The American crocodile, however, is a particularly silent species. Some scientists theorize that the reason for this is the difference in habitats; alligators live in more densely vegetative environments that do not transmit sounds as far, resulting in more private conversation. It is also probably that much crocodilian communication is subauditory or Òinfrasound,Ó or otherwise thus far undetectable to researchers, for example auditory or aqueous vibrations. This may be particularly true of our American crocodile friends. However, the calls of juveniles signaling distress will illicit help from even unrelated adults. In fact, researchers playing these calls from recordings have been attacked by adult crocodiles coming to the rescue. However they do it, it is apparent that crocodiles have used communication to set up complex dominance hierarchies. They are a regular feature of crocodilian daily life, with dominant individuals usually possessing large body size and aggressive temperaments. They are recognized by their fellow crocodiles as dangerous, and have access to the best mates, nest spaces, food, and living space. Subadult males and small females occupy low positions while large males rate the highest, as do the largest females in the female heirarchies. Dominant crocodiles are recognized by their approaching other individuals, while submissive individuals move away. It is also probable that body posturing tells individuals a lot about the status of the crocodiles they encounter. A dominant crocodile swims lazily at the surface, while lesser ones will submerge readily. Actual combat is comparatively rare, but dominant individuals grab lower-ranking ones at the base of the tail, where scarring or injury can occasionally occur. (Ross, 1989) Crocodiles are also territorial, defending large areas from males that pose a threat to their dominance or defending nest sites with ferocity. This behavior is however densitydependent and worst during the breeding season, a period of intense communication among crocodiles. The males first assert their position with increased aggression, and in American crocodiles large males fight with open

43

jaws directed at their rivals. Actual injury is rare but the victor will win dominance, giving him access to the choicest mates. He will express his power by patrolling his territory conspicuously on the surface and selfassertion with headslaps or vocalizations. A female, once attracted, will initiate courtship by indicating submission Ð she must divert the maleÕs aggression away from herself and into the courtship display, or risk serious injury by the male. In American crocodiles the snout-lifting behavior is used by the female to signify her receptivity to the male. He will copulate for several minutes and then, depending on the density, both may proceed to a number of other mates, or may copulate together repeatedly over the next several days. Much of the crocodile brain is occupied with feeding itself, and it is logical that much of their behavior is geared to this end. Crocodiles are generally idle hunters that lie in wait for their pray. They are adept at stealth and camouflage. Once they lunge, they are truly impressive predators; they can leap, run, and are incredibly fast and strong. They save energy in this manner. Cooperative hunting among crocodiles has been recorded, although not specifically among American crocodiles. In Africa they line up to block rivers so that migrating fish will be trapped against a barrier of crocodiles. They have been observed sharing foods that are too big for one animal to tear apart alone without apparent hostility, and they have been seen taking turns to dismember and eat a carcass. (Ross, 1989) These same crocodile barricades can be fatal to human beings, and human-crocodile interactions are generally unpleasant on both sides. American crocodiles are less aggressive than other crocodilian species and are not frequently implicated in man-eating attacks. American alligators, Nile crocodiles, and Indo-Pacific species are all known to attack humans more frequently than this species. V. A crocodileÕs life begins in the egg, buried with a clutch on the banks of a river or lake. Crocodiles lay eggs that are less brittle than bird eggs and bury them in mounds of rubbish and vegetation or sand. American Crocodiles are particularly known for digging hole nests, especially in Florida, but the extent of this behavior is not well known. Clutch size is typically in the 30Ð60 range, although in some populations mean clutch size is in the low 20s. As with most hole nesting species, C. acutus nests during the annual dry season with eggs hatching around the beginning of the annual rainy period. (Ross, J. 2000) The extent of parental care is varied Ð many females guard the nest assiduously, fasting until they hear the grunts of the young, and then dig them out, even cracking the eggs to release the hatchlings. In laboratory studies, the eggs of American crocodiles were seen to communicate even before hatching, where tapping sounds within an egg was replied to by neighboring eggs. It is possible that this communication facilitates the synchronized hatching of the clutch. Between 90 and 100 days after being laid the eggs hatch, right at the beginning of the rainy season. The young crocodiles are around 25 centimeters in length. They are less vocal than other crocodilians, and within a few days they move away from the nesting area. Other crocodilians have a much higher level of parental involvement, with the mothers guarding the juveniles and keeping them together for up to several years in family groups. It is possible that this behavior in American crocodiles is an adaptation to the high degree of hunting in the second quarter of the century (Alderton, 1998) and maternal care was more intensive in the past Ð groups are more easily hunted than individuals. Even once the hatchlings are free of the nest, they remain highly threatened for their vulnerable period of youth. Fish, birds, small mammals (especially raccoons and small cat species) all eat the young crocodiles. (Ross, 1989) Beyond one meter in length, mortality of crocodiles decreases. They have few natural predators, especially if they can avoid being caught on land, although occasionally subadult animals can be killed by snakes or large predators such as leopards. Females grow more slowly and reach maturity at a smaller size than males, who continue growing and usually exceed females in maximum size. Crocodilians can be long lived in the wild and there are records of particular individuals residing for decades (Ross, 1989) They will spend much of their time basking in the sun and hunting;

44

feeding is lowest in the cool periods of winter but increases with temperature during the spring and summer months. Crocodiles do not chew their food; large teeth impale the animals and then the crocodile positions it for swallowing and depends on gravity to move food down the gullet with a toss of their head. The greatest threat to adult crocodiles, besides human influence (the subject of another paragraph or probably another paper of its own) is other crocodiles, particularly for young males by larger males. However, cannibalism seems to be rarer than popularly believed. It is more frequently social than nutritional and often occurs in the breeding season. Females reach sexual maturity at lengths of 2.5 meters, regardless of age. When the mating season begins, an extended courtship period can last up to two months. (Britton, 2002) When it becomes time for the female to nest, she must be extremely careful in selecting the site. Nest mortality is high; even during the dry season, flooding can kill an entire clutch, especially in hole nests which can fall below the water level during periods of heavy rains. (Zappalorti, 1976) Crocodiles cannot adjust the temperature and humidity of nests like birds can, and the nest cannot be rebuilt. There is only one large clutch a year, unlike birds which lay several small clutches. The nests often flood or the eggs can drop in temperature below what is required for the embryos to survive. (Ross, 1989) Eggs require oxygen diffusion through the porous shell, so many can asphyxiate under imperfect conditions. Likewise, although many crocodiles guard the nest assiduously, predation is common among crocodile clutches. Small mammals, fungus, insects, and reptiles all dig out and consume the eggs. If the female can successfully protect her nest to the hatch, another cycle of crocodile life can begin. VI. The characteristics of the American crocodile described so far are especially significant when considering their needs for conservation. It is only through understanding the behavior and physiology of any species that we can know how best to serve them, and this species of crocodile is no exception. Unfortunately, the problems that loom large in the global environmental battlefront are especially relevant to crocodilians, which means there are no easy answers to their problems. For example, almost any issue of water quality has a direct impact on the American crocodile. Because of their almost exclusively fish diet, (Alderton, 1998) any influence on the aquatic food chain will work its way up to crocodiles. For example, eutrophication of lakes kills of algae and fish species, so even though crocodiles can endure brackish water quite well, they may still be lost if their prey species are eliminated. Furhermore, salinization of water resources is a problem for crocodiles; even though adults are quite adept in both salt and fresh water, the juveniles have larger surface area ratio and cannot survive in salty water. (Ross, 1989) Salinization occurs as water sources are depleted, a universal problem in our water-guzzling world. Even if the water can be to some degree protected, the crodociles are in an unfortunate situation: they require hundreds of kilometers of undisturbed wetlands (Ross, J. 2000) and large shallow bodies of water such as slow rivers, swamps, and marshes, because they require such a large territory for each individual. This is unfortunate because wetlands are being lost at a high rate all over the world. They are drained for farming or for pasturelands. Also, crocodiles avoid strong wind and wave action because they require calm water to swim effectively. It is theorized that the still water allows them to keep only the nostrils above water, but if it is windy the snout must be raised at a steeper angle. This makes it more difficult to swim. (Ross, 1989) The crocodiles therefore need protected waters and will avoid the open water if it is rough. This means that tree cover is important and deforestation can disturb their habitats even if water quality is preserved. VII. Crocodiles have faced over-hunting threats since the very dawn of human civilization. In fact at least one primitive terrestrial crocodilian, Mekosuches inexpectatus, was probably lost to human influence. Its extinction, in New Caledonia, occurred in less than 2000 years Ð it was gone before the arrival of Europeans and its rapid disappearance points to hunting by primitive peoples. (Ross, J. 2000) Our record has not improved much since

45

then. Crocodilians of all sorts have been widely hunted for hides, made into leather shoes and handbags, and have also been used for meat and traditional remedies and folk medicine. Of the 22 recognized varieties of crocodilians, at least 15 have been commercially exploited. (Thorbjarnarson, 1999) The effect has been universal and devastating. During the 1950s nearly 60,000 Nile Crocodiles skins were exported from East Africa. In 1926 36,000 American Alligators were bought in Lousinana. In 1888 a single hunter took 500 in one season, and another took 42 in a single night. (Ross, 1989) In South America it is largely Caimans that have been hunted for their ÒclassicÓ skins and that species has proportionally lost thousands of individuals. The American crocodile has not escaped this exploitation: the population in Isla Fuerta, on the Caribbean coast of Columbia, was driven to extinction when the mangrove forest was destroyed. Cattle ranching has removed nearly two-thirds of Central AmericaÕs primary forest, pushing the American crocodile there to the periphery of its range. The current low population size can be attributed to the extensive commercial harvesting that occurred from the 1930s into the 1960s. VIII. Before Spanish explorers came to Costa Rica, in the person of one Christopher Columbus in 1502, the native peoples were relatively scattered and, despite at least one well-developed city in the past, had a low degree of organization. The Spaniards killed most of the natives with their foreign diseases when they came to the Òrich coast,Ó although in actuality there was not much easily available gold. (Rosera and Palloni, 1999) The local species have been under assault ever since. Hunting was a fairly widespread problem in the country in the past, but today around twenty-five percent is protected lands and the American crocodiles are being given a chance to recover. In Costa Rica thereÕs a reported population of around 300 individuals in the Rio Grande de Tarcoles and around 35 in Estero Roto. (Ross, J. 2000) While these populations are considered viable, the standard minimum variable population (MVP) for any animal species is 500 individuals. (Rosera and Palloni, 1999) Habitat degradation continues, even in the well-protected island, and poaching problems can persist. In 1993 Costa Rican officials were forced to act when crocodiles were being killed following some attacks on humans. (Moyen, 2000) Because the large animals are predators and carnivores, it is natural for them to kill and even consume humans if given the opportunity. Public sentiment was strongly anti-crocodile, but it is slowly softening. The collection of adult breeders to stock farms could become a serious problem (see next paragraph) if not carefully regulated by the appropriate authorities. (Ross, J. 2000) IX. The current estimated wild population of American crocodiles is between 10,000 to 20,000 individuals. (Britton, 2002) There are only about 500 in the state of Florida, at the edge of the species range, (Alderton, 1998) and the rest are spread mostly (but not entirely) across Central America. Although the species has the widest range of any New World crocodile, it is depleted to a significant extent over most of its range and in a third of its range is quite dangerously low. The populations of a few regions, especially Belize and Cuba, are somewhat safe, and the Costa Rican range is to a lesser extent the same, but there is still much to be desired. C. acutus is completely protected in most countries where it occurs, (Britton, 2002) but the enforcement of this protection is often inadequate - although there are programs in 8 countries within its range, legislation is ineffective or poorly enforced. Crocodilians as a whole are threatened by hunting and habitat loss, and the black caimen, broad-snouted caimen, American crocodile, the Orinoco crocodile, the MoreletÕs crocodile, Nile crocodile and the Cuban crocodile are all listed on the CITES appendix of endangered animals. (Kricher, 2002) There are currently 12 species of crocodiles remaining, most of which are to some degree threatened by human activities. Since the increase in international conservation legislation from 1973 (Ross, 1989) numbers are increasing, but they are still poorly protected throughout most of their range. Today two million skins are harvested annually, mostly

46

caiman from south America, more than half taken from wild populations in violation of national wildlife regulations. Even though poaching is widespread, the real killer for crocodilians today is habitat destruction, and that will be the real battleground to protect crocodiles of all species in the future. X. All crocodiles, if given the chance, would choose to avoid humans; there is no need for our two species to compete. Today, however, because of increasing populations, increasing needs, and an ever-widening ecological footprint, we do not give crocodiles that chance. We can no longer afford to; in most cases human intervention has become necessary to protect genetic diversity and healthy populations for most crocodile species. Simply preserving the animals and their habitats is an important first step, certainly; since the 1970Õs, when we become aware that the devastation of the past was causing serious problems for crocodiles, many species have benefitted from improved protection and reduced exploitation. But it is widely recognized that Òthe majority of the species require a more creative approach that provides incentives to people living with crocodiles to offset their real and perceived costs. Sustainable use has become a key element in the conservation of crocodilian species.Ó (Ross, J. 2000) Crocodiles are not flagship species for conservation efforts. Local people tend to regard them, not unreasonably, as dangerous and unattractive to live near. When conservation programs succeed, human problems with crocodiles frequently escalate, (Ross, J. 2000) and the crocodiles often need continued protection. But today new methods of utilization and protection combined are providing a chance for

Caiman latirostris Broad-nosed Caiman (except the population of Argentina) • Status: Not Listed (IUCN 2000); Endangered (ESA) • Distribution: Argentina, Brazil, Bolivia, Paraguay, Uruguay • Threats: illegal leather products confiscated regularly (German Customs 2000); habitat destruction, illegal hunting (Ross 1998) • Keep: 49 males, 160 females, and 23 animals of unknown sex in captivity (ISIS 2000) • Breed: only ranching activities in Argentina, while captive breeding is known only from University of Sao Paulo, Brazil, where the first breeding in captivity was successful (Ross 1998, Verdade and Sarkis 1998); no offspring produced in past six months (ISIS 2000) Melanosuchus niger Black Caiman (except the population of Ecuador) • Status: Lower Risk: Conservation Dependent (IUCN 2000); Endangered (ESA) • Distribution: Bolivia, Colombia, Ecuador, French Guyana, Guyana, Peru • Threats: illegal leather products confiscated regularly (German Customs 2000); habitat destruction, illegal hunting (Ross 1998) • Keep: 4 females and 2 animals of unknown sex in captivity (ISIS 2000) • Breed: only a ranching program in Ecuador, experimental farming in Columbia and Bolivia (Ross 1998); captive breeding not successful (Sommerlad 1998); no offspring produced in past six months(ISIS 2000)

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Caimán Negro Melanosuchus niger Bibliografía

En esta presentación se encuentran las obras que hemos consultado en nuestros estudios del Caimán Negro (Melanosuchus niger). Incluimos citas a otras obras que tal vez sean de utilidad a quien necesite más información.

• Alderton, David. 1998. “Crocodiles & Alligators of the World” Blandford, London. 190 páginas. (ISBN: 0-7137-2382-3) (en inglés)

• Bartlett, R. D. y Patricia P. Bartlett. 2003. “Reptiles and Amphibians of the Amazon: An Ecotourist's Guide” University Press of Florida. Gainesville, Florida. 291 páginas. (ISBN 0-8130-2623-7) (en inglés)

• Behler, John L. y Deborah A. Behler. 1998. “Alligators & Crocodiles” Voyageur Press. Stillwater, Minnesota. 72 páginas. (en inglés)

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Bothwell,

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Richard.

1962.

The following crocodilian-related websites may be useful. Please note that many of these links will change as websites appear and disappear.

Essential information • • •

IUCN IUCN - SSC IUCN - Red List of Threatened Species

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CITES

Conservation, Management & Research in general

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Gharial Conservation Alliance (GCA) Crocodilians Natural History & Conservation The EMBL Reptile Database The Bibliography of Crocodilian Biology Tomistoma Task Force Crocodilian, Tuatara, and Turtles Species of the World Fauna and Flora International Florida Department of Agriculture and Consumer Services 'FL - Alligator.com' Florida Fish & Wildlife Conservation Commission's 'Alligator Management' National Library of Medicine's 'PubMed' (useful for searching for scientific publications on various crocodilians) Proyecto Jacaré (Español versión or English version), caiman conservation and ecotourism Yacare.net, the website for Argentine caimans Zoocriadero Cerros Azules, caiman conservation in Uruguay American University's 'Nile Crocodile Trade Case' CITES Resolution Conf. 11.12 'Universal tagging system for the identification of crocodilian skins' Conservation Biology: 'Economic Incentives for Management of Venezuelan Caiman' 'Crocodylomorpha: Overview' of crocodilian phylogeny and fossil history International Reptile Leather Federaton / Internationale Reptilleder Verband e.V. Offenbach 'Monitoring Caiman Population Trends on the Ibera Marsh' Systematic Biology: 'Data set incongruence and the phylogeny of crocodilians' University of Texas's 'The Visible Alligator Skull'

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University of Utah's 'Alligators on Treadmills Hint at How Dinosaurs Breathed'

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General Information & Captive Collections • • •

University of Florida's Electronic Data Information Source on 'Alligators and Crocodiles' University of Florida's 'Alligators and Crocodiles: Quick Reference Sheet' Discuss crocodilian issues on 'The Crocodilian List' 49

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Animal Planet's 'Ferocious Crocs' Burris Mill & Feed Alligator and Crocodile Feeds (search on Alligator 'Species Types') Clemson University's 'Crocodilians' Discovery Channel's 'What is a Crocodilian' Florida Power & Light's 'Crocodiles and Alligators Overview' The Paleosuchus Page by Collin Stevenson Mike Godwin's 'The Gator Hole' India4u.com's 'Crocodile Species in India' The Reptipage's 'Crocodylians' Kent Vliet's 'Crocodilians' St. Augustine Alligator Farm

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Crocodopolis

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Crocodilian Care • •

Crocodilian Captive Care FAQ Recommendations on the Care of Amphibians and Reptiles in Academic Institutions. Use the 'Find' function under your browser's 'Edit' button to search this site for 'alligators' and 'crocodiles'.

Reproduction

(Reed Books: Sydney); K. Richardson, G. Webb and C. Manolis (2000). “Crocodiles: Inside and Out” (Surrey Beatty and Sons: Sydney).

Crocodilians

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Online Journal of the IUCN-SSC Crocodile Specialist Group

Background Crocodilia was developed by the IUCN-SSC Crocodile Specialist Group to provide an international forum for the publication of articles on research on the world's 23 species of crocodilians. The journal is intended to have a broad focus, ranging from pure biology and ecology to management and conservation issues. We hope that contributions to the journal will add to our general knowledge and understanding of crocodilians and their role in the ecosystem, and improve our ability to manage and conserve wild populations throughout their range. Crocodilia invites contributions of original research, reviews on current management and conservation issues, methods or techniques papers and editorials. Recognising the extent of important "grey" literature that remains unpublished and unavailable to crocodilian researchers, Crocodilia will consider such articles for publication.

Access All contributions are published online (www.iucncsg.org) with open access.

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Review All contributions are peer-reviewed by at least three expert reviewers. Acceptable manuscripts will be returned to the author for consideration of comments and criticism.

Production Editor Charlie Manolis ([email protected])

Editorial/Review Committee Ruth Elsey, Louisiana Department of Wildlife and Fisheries, USA Richard Fergusson, Crocodile Conservation & Consulting (Pty) Ltd, Zimbabwe Craig Franklin, University of Queensland, Australia Sally Isberg, Porosus Ltd, Australia Valentine Lance, San Diego State University, USA Jeffrey Lang, University of Minnesota, USA Charlie Manolis, Wildlife Management International Pty. Limited, Australia Mark Merchant, McNeese State University, USA Chris Moran, University of Sydney, Australia Carlos Piña , CICyTTP-CONICET, Argentina J. Perran Ross, University of Florida, USA Grahame Webb, Charles Darwin University, Australia Allan Woodward, Florida Fish and Wildlife Conservation Commission, USA Alvaro Velasco, Wildlife: Products and Services, Venezuela Kent Vliet, University of Florida, USA (Note: Additional reviewers will be used as required)

Submission of Manuscripts New manuscripts should be sent as one (1) electronic file, in MS Word format containing complete text, tables and figures, as an e-mail attachment, to the Production Editor ([email protected]). The final, revised, accepted version of the manuscript should be submitted in electronic form, in MS Word (text, tables) and tiff (figures) format, as separate files. That is, the text, each figure and each table will comprise a separate file, labeled with the author's name and number (eg JonesText.doc, JonesFig1.tiff, JonesTable1.doc, JonesTable2.doc, etc.). Files can be sent e-mail attachments ([email protected]) or on CD (mail to: Editor - Crocodilia, P.O. Box 530, Sanderson, N.T. 0813, Australia). To facilitate the production process, please ensure that format conforms 52

to the journal style guidelines (see Guidelines for Authors). Manuscripts that do not conform will be returned.

Copyright Publications appearing in Crocodilia have been refereed and improved. These publications, and all parts thereof, are therefore protected by copyright. This covers the exclusive rights of the publisher to sell, reproduce (including photographic or electronic means), to distribute (including photocopies, reprints or electronic means), and to store this material. The acceptance conditions of a manuscript for publication automatically include the consent of the author(s) to transfer the copyright to the publisher. Permission for exceptions to these rules must be obtained in writing from the publisher at the time of manuscript submission.

Disclaimer Publisher, editors, reviewers and authors do not accept any legal responsibility for errors, omissions or claims, nor do they provide any warranty, express or implied, with respect to information published in Crocodilia.

Guidelines for Authors All manuscripts must written be in English. See example article for format.

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a ti o n. A v ai la bl e: h tt p :/ / w w w .g o b bl y g o o k. c o m . A c c e s s e d 1 1 A u g u st 2 0 0

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Enquiries should be addressed to: Crocodilia Crocodile Specialist Group P.O. Box 530, Sanderson, N.T. 0813, Australia Telephone: 61.8.89224500 Facsimile: 61.8.89470678 E-mail: [email protected]

Crocodile Specialist Group Newsletter The Crocodile Specialist Group Newsletter provides current information on the conservation, status, news and current events concerning crocodilians, and on the activities of the CSG. Quarterly intervals.

Proceedings of CSG Working Meetings Proceedings contain all papers presented at CSG Working Meetings held every 2 years. Proceedings up to the 16th meeting, are available from: Zoo Book Sales, 403 Parkway Ave. N., P.O. Box 405, Lanesboro, MN 55949-0405, USA [Tel: (1) 507 4678733, Facs: (1) 507 4678735; http://www.zoobooksales.com; E-mail: [email protected]]. Proceedings of 17th meeting are available from Wildlife Management International, P.O. Box 530, Sanderson, N.T. 0812, Australia (E-mail: [email protected]). Proceedings of the 18th meeting are now only available on disk (as PDF version). A listing of all publications that have appeared in CSG Proceedings up to the 16th CSG Meeting are at the Florida Fish and Wildlife Cooperative Research Unit webpage (http://www.wec.ufl.edu/coop/CSGbib.htm).

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The Action Plan for Crocodile Conservation It was first published in printed form in 1992, but a revised and continuously updated version now is available on the web. Printed Edition Crocodiles: An Action Plan for Their Conservation. 1992. J. Thorbjarnarson, compiler; H. Messel, F.W. King & J.P. Ross, editors. IUCN Gland Switzerland. 136 pp. ISBN 2-8317-0060-4. Comprehensive accounts of species status by country and recommended conservation actions, with extensive bibliography. [Out of print.] WWW Edition Status Survey and Conservation Action Plan: Revised Action Plan for Crocodiles 1998. J.P. Ross (ed.). IUCN–The World Conservation Union, Gland, Switzerland. World Wide Web Edition. The web edition is published in a form that allows each species account to be printed out complete with bibliographic references.

CITES Identification Guide - Crocodilians Environment Canada has produced a series of identification guides, including one for crocodilians, specifically designed to assist individuals responsible for the application of CITES in various countries. The Guide provides a simple, visual approach that facilitates the identification of several crocodilian species that are traded and require CITES permits.

International Trade in Crocodilian Skins Review and analysis of the trade and industry dynamics for marketbased conservation. 2002. James MacGregor. The definitive authority on international trade and markets in crocodilian skins.

Reports/Publications/Articles Various CSG reports, research publications and articles featured in the Newsletter are available as PDF versions.

Species Accounts

Melanosuchus niger 56

Common names: Black caiman, Jacar� assu (also a�u, uassu, gua�u), Jacar� negro, Caim�n negro, Caim�n, Cocodrilo Range: Bolivia, Brazil, Colombia, Ecuador, French Guiana, Guyana, Peru Revised by John Thorbjarnarson

Conservation overview CITES: Appendix II in Ecuador (ranching) subject to quota from 1997; Appendix I in all other countries. CSG Action Plan: Availability of Survey Data � Poor Need for Wild Population Recovery � High Potential for Sustainable Management � Moderate 1996 IUCN Red List: EN. Endangered. Criteria A.1.c. d. Inferred decline >50% in 3 generations, exploitation over much of range. Current recovery may be trending toward Vulnerable. Principal threats: Illegal hunting, habitat destruction.

Ecology and natural history The black caiman is the largest member of the Alligatoridae, with adult males surpassing 4m in length. This species is widely distributed throughout the Amazon River basin, but populations are also known from peripheral areas outside the Amazon (the Rupununi and upper Essequibo River drainage in Guyana; the Kaw region of French Guyana; Vasquez 1991). Until recently the black caiman had been little studied. However, during the 1980s research on wild and captive populations was carried out by Herron and collaborators (1985, 1990, 1991, 1994) in southern Peru, Pacheco (1990a and b, 1993a and b, 1994) in Bolivia, and Asanza (1985, 1992) in Ecuador. Ecological studies are presently being carried out in Brazil (Sociedade Civil Mamirau�), Ecuador (EcoCiencia), and Colombia (Universidad Nacional de Colombia). Additionally, information on aspects of the ecology of this species was gathered during survey work conducted by Brazaitis et al. (1990a and b), and King and Videz-Roca (1988). Hines and Rice (1992, 1994) have conducted recent surveys of population status in Ecuador. Gorzula and Woolford (1990) surveyed black caiman in the Essequibo region of Guyana. These studies have augmented the work done by Medem on this species in Colombia throughout the 1950s, 1960s and 1970s (Medem 1981), and the studies of Otte (1978) in Peru. The black caiman occupies a wide variety of habitats including large rivers and streams, oxbow lakes, and in some areas seasonally flooded savannas. Ecological habitat partitioning between this species and the other Amazonian caimans appears to be taking place in many areas, but habitat relations among the species have been blurred by the severe reduction in numbers of black caiman in most areas (Magnusson 1982). Herron (1994) found that common caiman and black caiman were spatially separated in a Peruvian oxbow lake. Fittkau (1970) hypothesized that black caiman played a vital role in nutrient cycling in the rivers and mouth-lakes of the lower Amazon. The demise of Melanosuchus populations has been linked anecdotally with a decrease in

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fisheries productivity. However, little ecological evidence is available to confirm or refute these ideas. Peres and Carkeek (1993) provide an interesting account of how large caiman populations in the Brazilian Amazon protect fish stocks by destroying fishing nets. The black caiman, like all alligatorids, is a mound nester, however, many aspects of this species� reproductive ecology are poorly known. Available information suggests that females reach sexual maturity when ca. 200cm total length (TL). Mean adult female size is 280cm TL, and clutch size averages 39.3. Melanosuchus lays very large eggs averaging 143.6g (Thorbjarnarson 1996). Herron et al. (1990) report on a Melanosuchus nest in Peru observed throughout the entire period of incubation. Pacheco (1990a and b) presents information on the reproduction of captive Melanosuchus in Bolivia.

Conservation and status Commercial hunting of the black caiman did not begin in earnest until the 1940s, when stocks of the South American crocodiles (Crocodylus acutus, Crocodylus intermedius) were becoming very low. Hunting peaked during the 1950s, and declined markedly through the 1960s, when trade in Caiman crocodilus began to increase. However, in some areas significant trade in black caiman extended into the 1970s (Plotkin et al. 1983, Gorzula and Woolford 1990). Commercial hunting continues to be a problem in some areas. In the upper Amazon of Brazil, most hunting is for the sale of meat which is reportedly sold in Par� or Leticia. Ecological competition with the smaller common caiman may also be playing an important role in slowing natural population recovery (Magnusson 1982, Brazaitis et al. 1988). Some recent census work has been conducted throughout most of the range of the black caiman. Although it is widely distributed (principally in the Amazon basin) past overhunting and continued poaching has drastically reduced populations. Populations of black caiman are considered to be severely depleted in four of the seven nations in which the species occurs, and are depleted in the remainder. Relatively good populations remain scattered in isolated areas of Guyana, Peru, and Ecuador, particularly in oxbow lakes and other marshy, nonriverine wetlands where access is difficult. The population in the Kaw region of French Guiana has been decimated by hide hunting, and in Bolivia and Colombia black caiman appear to be still widely distributed, but occur in low numbers. Some Brazilian populations are locally dense but in most areas they represent but a small fraction of their former levels. While commercial exploitation has been illegal and minimal in recent years, people throughout the region continue to utilise black caiman for other purposes. The fat is collected for medicinal purposes and the meat is reportedly used to bait traps for edible tortoises. For human consumption, the meat of black caiman is considered rank and, in comparison to the meat of Caiman and Paleosuchus, is poorly regarded by indigenous people, (Ortiz van Halle 1995, Alvarez 1995). Ecuador is initiating a trial ranching program. In all other countries management programs for the black caiman are exclusively based on the legal protection of wild populations. However, as in the majority of developing countries, the enforcement of these laws is difficult. Columbia Black caiman were at one time abundant in the Colombian Amazon region from the southern city of Leticia to the R�o Atacuari along the border with Peru, and in the Putumayo, Caquet�, and lower Apaporis rivers (Medem

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1981; Plotkin et al. 1983). Commerial hide hunting began in the 1940s and populations were rapidly depleted. Wild populations of black caiman have been virtually extirpated in Colombia. Surveys by biologists in the 1970s found very few individuals in the Amazon and Putamayo region (Medem 1981, Plotkin et al. 1983). Based on interviews in the vicinity of Leticia, Pachon and Rios (1993) believe that little hunting is currently taking place and populations are slowly recovering. However, only three adults were seen during five diurnal foot surveys, and none were observed during nocturnal counts by boat. Additional surveys and ecological studies were planned for 1994�95. Melanosuchus were legally protected in Colombia in 1969 with the implementation of a total ban on hunting (Resolution No. 411). Hunting and egg collection is also specifically banned for Melanosuchus (INDERENA Resolution No. 573 of 1969; Plotkin et al. 1983), but little enforcement has been in effect and significant commercial hide hunting continued into the 1970s. Recently, it has been reported that Melanosuchus has been removed from the list of totally protected species because population status was judged to be secure in well protected habitat (Jenkins et al. 1994). One farm was reported to be registered for experimental captive breeding of black caiman (breeding stock 2 males, 8 females in 1994). However, INDERENA officials have stated that commercial exploitation would not begin before a wild population monitoring program was established and the farm registered under CITES regulations (King 1994). Ecuador In Ecuador, Asanza (1992) reports that Melanosuchus was heavily exploited between 1930 and 1970, with approximately 500,000 skins being traded, mostly through Leticia and Manaus. In the 1970s, Medem (King 1973) believed that Ecuador was the only place where Melanosuchus was not on the verge of extinction. Populations are known to exist in several parts of the Ecuadorian Amazon, particularly in isolated oxbow lakes. Miyata (in Groombridge 1982) reports that the species may be relatively common in the lower R�o Aguarico and the R�o Yasuni-Lagartococha area near the Peruvian border. The Zancudococha population appears to be a healthy one with an estimated population size of 100 to 150 (Jahoda 1990, Bowes 1992); however, based on two years� census data, Asanza (pers. comm.) estimated the total population size to be 260, with a mean density of 23/ km. Asanza (1992) reports that significant populations are still found in the Aguarico River system (Cuyabeno lakes and river, Imuya Pacuya and Zancudococha lakes, and the Cocaya River), the Napo River system (Jivino, Indillana, Tipitini and Yasuni rivers, and Limoncocha, Taracoa, Arango, Challuacocha, Panacocha, Garzacocha and Jatuncocha lakes), the lower Nashino and Cononaco rivers, the lower and middle Curaray River, the lower Pindoyacu, the lower Yaupi and upper Morona, and the Pastaza River system (Bufeo, Capahuari, and lower Ishpingo rivers). Population densities in the Cuyabeno region have been relatively stable since 1978, with mean values of 5.68/km in the lakes and 3.15/km in the lakes and rivers. Densities in Zancudococha (23.5/km) and Lagartococha (23.6/km) lakes have been high based on five and two years of surveys respectively. However, Asanza (1992) reports a decline in the population of Melanosuchus in Limoncocha between 1983 and 1990. Hines and Rice (1992, 1994) conducted caiman censuses in Ecuador during 1992 and 1993 along 18 survey routes (131.2km total) of optimal habitat. Black caiman were observed at 16 of 17 locations and densities ranged from 0/km to 13.25/km, with a mean value of 4.65/km. The highest densities were found at Challuacocha (11�13/km), Lagartococha (up to 13.25/km), and Limoncocha (10.25/km). In a total of 28 surveys, 309 Melanosuchus and 188 Caiman were observed. The size class distribution reflected an abundance of juvenile animals.

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The black caiman was not protected in Ecuador by the wildlife resolution of 1970, but is included in the total ban on export of commercial wildlife (Plotkin et al. 1983). Asanza (1982) reports that Decreto 487 (of 1980) and Ley No. 74 (1981) prohibit the commercial hunting of all reptiles and the export of indigenous species. The population in Limoncocha is protected as result of the site being a research station. Efforts are underway to have the Zancudococha lagoon included in the national park system, and a biological station similar to the one on Limoncocha established (Asanza, pers. comm.). In 1995�6, population surveys and ecological research on black caiman in and around the Yasuni National Park were planned by EcoCiencia, an Ecuadorian NGO, as part of the SUBIR (Sustainable Use of Biological Resources) project. In the late 1980s, an illegal trade in small (40�120cm TL) live Melanosuchus was reported. Although their final destination is unknown, numbers of these animals were reported to be illegally exported over the Colombian and Peruvian borders (Asanza, pers. comm.). At the 1994 CITES meeting, a ranching program for Melanosuchus in Ecuador was approved. This program will be managed by the government wildlife management authority INEFAN. However, due to questions pertaining to the readiness of the management program, a two-year zeroexport quota was voluntarily agreed to by the Ecuadorian authorities. Ecuador has drafted a management plan for the ranching program, and assigned an INEFAN representative to manage it. A three-year trial program will collect a maximum of 1,500 eggs and/or hatchlings per year, with only one company licensed to participate. INEFAN and the company will jointly conduct population monitoring. All captive animals will be tagged, and exported skins will not exceed 2.2m in length. Provisions will also be made to permit export of live animals (up to 15% of the export quota, of one sex only). Peru Plotkin et al. (1983) considered the black caiman to be on the verge of extinction in Peru. Historically the species was common throughout the upper Amazon drainages in Peru, but was depleted by hunting which began around 1950 (Plotkin et al. 1983). Surveys by Otte (1974) found no Melanosuchus along the Sotileja, Heath and the Pariaman� Rivers, but some black caiman were observed in the upper R�o de las Piedras. Based on information from caiman hunters and skin buyers, Otte (1974) concluded that exploitable populations were only found in the upper regions of the Tambopata, Man�, Piedras and Amigo Rivers. More recently, viable populations were observed in lagoons along the Tampopata River (Plotkin et al. 1983), and some evidence suggests that populations may be recovering in the Manu-Madre de Dios region. Population surveys have been conducted in Cocha Cashu in Man� National Park since the early 1970s. Otte (1974) estimated a population size of 37 in 1971�1972. Similar counts carried out in 1978 suggested a 50�60% increase in population size. A census in 1982 estimated population size to be 213 (Vasquez 1982�3). During nocturnal counts in Cocha Cashu (4.0km) by Herron (1985), 99�111 black caiman were sighted (uncorrected population estimate; density = 24.74�27.75/km shoreline), with a population heavily skewed towards juveniles. Researchers studying otters in the Manu region indicate that the park contains a good population of black caiman, with smaller numbers being found in the Madre de Dios River, the Rio de los Amigos, the Rio de la Torre, the Rio Tambopata, and the Rio Heath (C. Schenck and E. Staib, in litt., 6 August 1993). In the Manu park, black caiman were seen in the cochas (oxbows) of Cashu, Lagarto, Brasco, Salvador, Huarez and Garza. Another small population remains in the Pacaya-Samiria National Reserve. Nocturnal counts in the Samiria river found a mean Melanosuchus density of 0.28/km (Verdi et al. 1980). During the early 1970s, Vasquez (1981) conducted nocturnal counts of black caiman in the Jenaro Herrera region and found densities of 0.46/km in lake

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habitat to 3.11/ha in swamp areas (4.5ha surveyed). Vasquez (1982�3) suggests that Melanosuchus populations have recovered to some degree since the decline in illegal hide hunting. Hunting of black caiman is prohibited in all cases except for subsistence purposes, although in some areas illegal commercial hunting continues (Plotkin et al. 1983). Ecological studies of Melanosuchus in the Manu region have been conducted by Otte (1978), Herron (1985, 1991, 1994) and Herron et al. (1990). Bolivia Black caiman were historically widespread throughout northern and eastern Bolivia, but were heavily impacted by hide hunting during the period 1942�1960 (Plotkin et al. 1983). Surveys in 1986�1987 found black caiman to still be distributed throughout most of its historical range, but in very low numbers (King and Videz Roca 1989). Of the very few individuals that were encountered, most were juveniles or sub-adults. Recent surveys in certain parts of the Beni and Santa Cruz lowlands indicate that populations in some areas are still locally abundant. Melanosuchus was found to be relatively abundant within the Beni Biological Station protected area (Pacheco 1993). Densities in six lagoons ranged from 0.47�19.5 individuals/km. Densities of M. niger in rivers were lower (to 1.4/km), but Pacheco considers the Beni Biological Station to harbor an important population of this species. Surveys conducted in rivers in the Rios Blanco y Negro Wildlife Reserve in Santa Cruz have found densities of 1.4/km in the Rio Negro (168km surveyed) and 0.9/km in the Rio Blanco (A. Taber, pers. comm.). Surveys in lakes have not yet been conducted. Reports also suggest the presence of localized populations in floodplain lakes along the Rio Itenez within the Noel Kempff Mercado National Park (D. Rumiz, pers. comm). Prior to 1979, Bolivian laws permitted the legal cropping of wild Melanosuchus populations (Decreto Supremo 08063 of 1967). Hunting was prohibited between 31 July and 1 January, and the minimum legal size was 2.5m (Medem 1983). Nevertheless these regulations had little effect in controlling the widespread hunting. Presently, the species is fully protected under Decreto Supremo 16606 of 1979 (Klemm and Navid 1989), but some illegal hunting continues (King and Videz-Roca 1989). Pacheco (1990a and b, 1993a and b) presents information on captive breeding and rearing of Melanosuchus in Bolivia. In August 1990, a total of 25 adult black caiman (>2.2m TL) were released in the Laguna Normandia, located adjacent to the Beni Biological Station near San Borja. These animals came from a group of approximately 150 captive individuals on the El Dorado cattle ranch. They had been brought there in the late 1970s for the establishment of a commercial farm. The release project was sponsored by PRODENA, a Bolivian conservation group, in association with the Beni Biological Station and the owners of El Dorado. Monitoring showed that only a small percentage of these animals remained in the lagoon (Vaca 1992). Pacheco (1995) reports that 8�10 of the group remain resident and reproduction was observed in 1995. Brazil Black caiman were at one time found throughout much of the Brazilian Amazon, but today have been extirpated from many of these areas (Plotkin et al. 1983, Brazaitis et al. 1992). Hide hunting was particularly intense in the early 1950s (Fittkau 1973), but was still in evidence in the late 1970s (Magnusson 1979). Magnusson (1979) reported a small population of Melanosuchus in the Tapajos National Park. The largest concentration was in a small lake, Lago das Piranas, where a total of 16 individuals were seen over a distance of 3km. Brazaitis et al. (1988, 1990a and b, 1992) report that the species is seriously depleted throughout central and southern Brazil.

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Of 47 sites in the Amazon basin, localized populations were only found at six sites: the R�o Galera in Mato Grosso, the R�o Madeira (Borba) in Amazonas, the Lago Comprido, Pracuba in Amap�, parts of the Rio Branco and Rio Ajarani in Rondonia, the Rio Amazonas at Paran� do Trinidade, Amazonas, and the Rio Uraricoera, Igarap� Grande, in Rondonia. Magnusson et al. (1994) report a low density of black caiman in the Anavilhanas Archipelago in the Rio Negro, and that some nesting is taking place. Peres and Carkeek (1993) note that although populations of Melanosuchus were intensively hunted in the Brazilian Amazon, and that small-scale hunting for meat continues, populations of both Caiman crocodilus and Melanosuchus niger are recovering in parts of the Amazon and its major tributaries, and illustrates this claim with their experience in the Rio Juru�. In June�July 1994, R. da Silveira (pers. comm.) censused over 700km of rivers, streams and lakes within the nearby Mamirau� Ecological Station. Although these surveys were done during a period of high water, Melanosuchus were observed at low densities at most sites within the reserve. Population surveys by Silveira during lower water periods (October) have demonstrated a healthy population of Melanosuchus, with some densities in excess of 30 individuals/km. In Brazil, commercial hunting, farming or ranching of the black caiman is prohibited. Illegal hunting continues throughout much of the Amazon. In the Mamirau� Ecological Reserve, dry season hunting for caiman is widespread, with the meat being sold in Leticia (Colombia) or along the lower Amazon (Par�) as piraruc� fish (Arapaima gigas) (da Silveira, pers. comm.). Peres and Carkeek (1993) suggest that this trade is widespread in the Brazilian Amazon. No hide hunting is reported.

Black caiman, Melanosuchus niger, Mamiraua, Brazil, where a substantial population of this depleted species is reported to be recovering. Photo by J. Thorbjarnarson. Guyana Medem (1983) reported that the black caiman was restricted to the upper and middle Essequibo, Rupununi, Rewa, and Berbice Rivers, as well as to two Amazon basin rivers (the Takatu and the Ireng) in Guyana. Gorzula

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and Woolford (1990) noted a similar distribution but were unable to confirm the reports from the Berbice River. Medem�s survey (1983) found black caiman to be close to extinction in Guyana following a period of intensive hide hunting. During the period of peak hunting, Guyanese residents would apply for permits, then have Brazilian hide dealers from Boa Vista cross the border and organize hunting parties of local Amerindians (Plotkin et al. 1983). Gorzula and Woolford (1990) reported that large-scale commercial hunting took place from 1955 to 1965, and that most of the skins went out via Brazil. Some hunting was reported into the 1970s. The survey by Gorzula and Woolford (1990) found that Melanosuchus populations had apparently made a recovery in the northern Rupununi region, where they were locally abundant. The overall mean uncorrected population density was 7.4/km (41.2km surveyed). They estimated the total population in the North Rupununi Savanna region to be 2,000�4,000 non-hatchlings. Anecdotal reports suggested that a similar population recovery was taking place downstream to the Tambio Inlet on the Essequibo River. Following a period of intensive hunting, the Guyanese government initiated a five year ban on caiman hunting in 1968 (Plotkin et al. 1983). As with Caiman, this species was classified as a game animal under the Fisheries Regulations of 1966 (Klemm and Navid 1989). No management program is currently in operation. French Guiana In French Guiana, black caiman are found in the coastal Kaw region in the northeast of the country, principally in the seasonally flooded grasslands bordering the Kaw River, and in the neighboring Savanne Angelique swamp. Smaller numbers of black caiman were also reported from the area between the lower Approuague River and the Ounary River located to the east of the Kaw, and in the small Ouapou Creek to the south of the Montagnes de Kaw. Formerly, Melanosuchus was also known from areas to the west of the Kaw including the Gabrielle Creek, and the Mahury River, but has since been extirpated. Along the border with Brazil black caiman were known from the lower Oyapock River and its tributaries, but have been virtually eliminated from this area by Brazilian hunters (Plotkin et al. 1983). The population in the vicinity of the Kaw was reported to be quite large, but has been severely impacted in recent years by hide hunting (Plotkin et al. 1983). Recent surveys by Behra (1994a) have confirmed the presence of Melanosuchus in the Kaw Swamp and in the Approuague River, but reported that they are absent from the Onanary and Kourouai Rivers. In the Approuague River, the caiman are living in an estuarine environment near islands where freshwater enters the river (Behra 1994a). Most of the animals observed by Behra during a 1993 survey were juveniles, and he suspects that the population increased between 1989 and 1993. Black caiman were protected in French Guiana in 1968 (Plotkin et al. 1983) but this law apparently did little to stop the commerce in Melanosuchus skins. Stronger legislation was enacted in 1975 which was not immediately effective, but resulted in officials seizing skins and appears to have reduced illegal trade (Plotkin et al. 1983). Black caiman are included in Article 1 of the Decree No. 77- 1295, which provides complete protection throughout the country (Behra, in litt 13 July 1990). This species is also protected in the newly designated Kaw Swamp Sanctuary (Behra 1990). However, Behra (1994a) reports that night time hunting of other crocodilians is allowed, making protection of black caiman difficult.

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Black caiman, Melanosuchus niger, Kaw River, French Guiana. Photo by M. Blanc. Venezuela Donoso-Barros (1966a, 1996b) reported Melanosuchus in Venezuela, citing a specimen from the Rio Negro originating from the region south of Cocuy. Gorzula and Paolillo (1986) noted the imprecise locality data, and cited Medem (1983) for a lack of confirmed specimens from Venezuela. Based on their observations in Bolivar and Amazonas states they concluded that no firm evidence suggested Melanosuchus to be found within Venezuela. King (1991) reported a black caiman killed just southeast of Puerto Ayacucho (presumably in or around the Rio Cataniapo) in 1967 by Jay Wilson, a caiman hide dealer. King (1991) suggests that this area and other sites in the upper Orinoco be revisited to confirm this record.

Priority projects High priority Population Status Surveys: The lack of population status information throughout the species� range is a major limiting factor for the development of conservation and management programs for this species. Countries such as Colombia are interested in developing management programs based on controlled commercial utilization, once adequate information has been obtained on the species status in that country. Very little information is available from throughout most of Brazil, Bolivia, French Guiana (particularly the Kaw Swamp), and Peru. There is anecdotal evidence that population recovery is taking place in certain areas, and this needs to be documented through systematic survey work. Historically, Marajo island at the mouth of the Amazon held huge populations of black caiman which were killed off by ranchers. Recent reports of a recovering population should be investigated. In Ecuador, basic surveys have been carried out, but need to be continued in the form of population monitoring as part of the ranching program. Basic Ecological Studies: Although it has a wide distribution and in some areas is found in locally dense populations, few ecological studies have been conducted on Melanosuchus. Certainly, in comparison to Caiman crocodilus, very little is known about black caiman. Ecological investigations now underway in Brazil at the

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Mamirau� Ecological Station should be continued and expanded. Ecological studies should be incorporated into the ranching and population monitoring program in Ecuador. Initiate management programs in Brazil: Brazaitis et al. (1988) strongly urged the development of a coordinated management program for black caiman and the other crocodilians in Brazil. This program should include long-term ecological investigations in areas such as the R�o Guapore (near Guajara Mirim and Costa Marques) and the R�o Galera in Mato Grosso. Several sites in Amazonas state, particularly the Mamirau� Ecological Reserve, are good candidates as well. Regional management coordination: Coordinated efforts between the range states of this species to develop compatible sustainable use programs and to control illicit trade are needed. Efforts need to be directed at controlling the illegal sale of caiman meat (including international control of the trade in meat between Brazil, Colombia, and Peru, particularly in Leticia) as a first step towards evaluating the potential for controlled commercial management. Initiatives to achieve this are underway under the auspices of the Amazonian Treaty and under the leadership and coordination of Colombia.

Visit these reference and conservation sites dedicated to the crocodilian species.

Crocodilians: Natural History & Conservation

Crocodile Specialist Group

The Gator Hole

Tim Wiegmann's Crocodile Library

kingsnake.com: Alligator & Crocodilian Forum

Animal Diversity Web: Order Crocodylia

The Crocodile Hunter Fan Site

Ask a Croc Expert Dr. Adam Britton first became fascinated by betoothed crocodyliforms when he was about 5 or 6 years old. Crocodilians have been his obsession ever since. The doctor of zoology is currently a research officer with Wildlife Management International. His research has focused on crocodilian biology, behavior, ecology and conservation management as well as bioacoustics and sensory capabilities of crocodiles. Britton has consulted on a number of documentaries and movies on crocodiles, including Discovery Channel's Ultimate Guide to Crocodiles and Crocodile Dundee in L.A.. Britton is also the author of crocodilian.com, a comprehensive online guide to information on crocodiles and alligators.

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Read Dr. Britton's responses to your croc questions, below. Crocodile Predators Crocodile Speed Croc/Human Interaction Crocodile Size Crocodile Hunting Crocodile Defense Alligators vs. Crocodiles Crocodile Mothering Crocodile Infections Crocodile Bites Crocs in Water Croc Body Heat

doi:10.1016/j.biocon.2006.07.009

Copyright © 2006 Elsevier Ltd All rights reserved.

Genetic structure, population dynamics, and conservation of Black caiman (Melanosuchus niger)

Benoit de Thoisya,

,

, Tomas Hrbekb, c, Izeni Pires Fariasb, William Rangel Vasconcelosb and Anne

Lavergnea, d a

Association Kwata, BP 672, F-97335 Cayenne cedex, French Guiana

b

Universidade Federal do Amazonas (UFAM), Departamento de Ciências Biológicas, Laboratório de Evolução e

Genética Animal, Mini Campus ICB, Av. Gen. Rodrigo Octávio Jordão Ramos, 3000 – Coroado, CEP 69077-000, Manaus, AM, Brazil c

University of Puerto Rico – Rio Piedras, Biology Department, Box 23360, UPR Station San Juan, PR 00931-

3360, Puerto Rico d

Institut Pasteur de la Guyane, BP 6010, F-97306 Cayenne cedex, French Guiana

Received 27 March 2006; revised 18 June 2006; 66

accepted 17 July 2006. Available online 27 September 2006.

Abstract Microsatellite DNA polymorphisms were screened in seven populations of the largest Neotropical predator, the Black caiman Melanosuchus niger (n = 169), originating from Brazil, French Guiana and Ecuador. Eight loci were used, for a total of 62 alleles. The Ecuadorian population had the lowest number of alleles, heterozygosity and gene diversity; populations of the Guianas region exhibited intermediate diversities; highest values were recorded in the two populations of the Amazon and Rio Negro. During the last century Melanosuchus populations have been reduced to 1–10% of their initial levels because of hunting pressure, but no strong loss of genetic diversity was observed. Both the inter-locus g-test and the Pk distribution suggested no recent important recovery and/or expansion of current populations. On a global scale, the inter-population variation of alleles indicated strong differentiation (FST = 0.137). Populations were significantly isolated from each other, with rather limited gene flow; however, these gene flow levels are sufficiently high for recolonization processes to effectively act at regional scales. In French Guiana, genetic structuring is observed between populations of two geographically close but ecologically distinct habitats, an estuary and a swamp. Similar divergence is observed in Brazil between geographically proximate “black water” and “white water” populations. As a consequence, the conservation strategy of the Black caiman should include adequate ecosystem management, with strong attention to preservation of habitat integrity. Distribution of genetic diversity suggests that current populations originated from the central Amazonian region. Dispersal of the species may thus have been deeply influenced by major climatic changes during the Holocene/Pleistocene period, when the Amazonian hydrographic networks were altered. Major ecological changes such as glaciations, marine transgressions and a hypothesized presence of an Amazonian Lake could have resulted in extension of Black caiman habitats followed by isolation. Keywords: Black caiman; Melanosuchus niger; DNA microsatellite polymorphism; Population dynamics

Article Outline 1. Introduction 2. Material and methods 2.1. Study sites and sample collection 2.2. Microsatellite genotyping 2.3. Genetic analysis 3. Results 3.1. Genetic diversity 3.2. Gene flow and structuring of populations 67

3.3. Population trends 4. Discussion Acknowledgements References

Journal of Herpetology Article: pp. 181–192 | Abstract Volume 33, Issue 2 (June 1999)

Diets of Spectacled and Black Caiman in the Anavilhanas Archipelago, Central Amazonia, Brazil Ronis Da Silveira and William E. Magnusson Coordenação de Pesquisas em Ecologia, Instituto Nacional de Pesquisas da Amazônia, Caixa Postal 478, 69011-970 Manaus Amazonas, Brasil Options: • • •

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Ronis Da Silveira William E. Magnusson Stomach contents were collected from 213 Caiman crocodilus with snout-vent lengths (SVL) between 15 cm and 115 cm, and 25 Melanosuchus niger with SVLs from 15 cm to 95 cm, in the Anavilhanas Archipelago, Rio Negro, Central Amazonia. The prey types consumed by the two species were generally similar. However, fish were common in the diet of C. crocodilus but absent from the M. niger. Snails (Pomacea) occurred in 24% of stomachs of M. niger, but in only 2% of C. crocodilus. The mean mass of food and the mean proportion of fish consumed increased, while the mean proportion of terrestrial invertebrates decreased significantly with the size class of C. crocodilus. The mean proportion of molluscs consumed increased significantly with the size class of M. niger, but there was no relationship between the mean mass of food or the mean proportion of other prey categories and size class in this species. However, the sample included only subadults. The mean size of all prey consumed, and of fish, increased significantly with size of C. crocodilus. However, there was no relationship between the mean size of prey in the categories terrestrial invertebrates, shrimps, or crabs, and the size of C. crocodilus. The mean size of all prey consumed was positively related to the size of M. niger. The mean mass of food consumed by C. crocodilus varied with the water body type (lake or canal), but there was no effect of season as indexed by the water level of the Rio Negro. Seasonal variation in the proportion of fish, terrestrial invertebrates, and shrimps consumed by C. crocodilus differed among water body types. Empty stomachs occurred in 24% of

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the C. crocodilus and 20% of the M. niger. Individuals with food in the stomach had eaten small volumes, suggesting that the caiman are unlikely to impact fisheries in the region.

Wilderness and Environmental Medicine: Vol. 17, No. 4, pp. 267–270.

Caiman Bite George Hertner, MD, FACEP From the Memorial Hospital Emergency Department and Department of Hyperbaric Medicine, Colorado Springs, CO

Caiman crocodilus, commonly called the spectacled caiman, is a very widely distributed resident of the western-hemisphere wetlands. Caiman bites to humans can cause trauma and infection. There are few reports of caiman bites; however, there is information about bites by other members of the same family, including Alligator mississippiensis. A case of acute caiman bite to the hand is described, including initial treatment and outcome. The bite resulted in multiple lacerations, interarticular fracture, and infection. One of the lacerations was closed, and the patient was started on moxifloxacin hydrochloride. Preventive care and treatment including wound care and antibiotics are discussed. The patient recovered with only a slight long-term functional deficit. Key Words: caiman, bite, attack, alligator, crocodile, Caiman crocodilus

Introduction Return to Top Caiman crocodilus (Figure 1

), commonly called the spectacled caiman, belongs to the family Crocodylidae

and subfamily Alligatoridae. All caimans are quite violent during initial capture and are unpredictable when aggravated.1,2 Caiman bites to humans pose several clinical problems.3–10 The force of the bite itself produces crush injuries, fractures, and soft tissue injury. Bite force is proportional to animal size and complicated by head thrashing.10 The teeth often leave multiple puncture wounds, and the animals tend to thrash once they have bitten down, leading to skin tears and further injury. The location of caiman habitat and attacks could lead to drowning. Delayed sequelae could include infection, tetanus, and retained foreign body.

Case report Return to Top The patient, a 37-year-old man, traveled to Brazil during January with a group of researchers doing collections and specimen study for an upcoming museum exhibit. They spent a part of their time on the Rio Negro section of the Amazon Basin, approximately 150 km south of the equator. The patient was involved in catch-and-release studies of caimans, concerned mostly with size data. While being captured in a wire snare, a 180-cm spectacled

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caiman bit down on the patient's left hand. The caiman, once closing its mouth, proceeded to shake and bite down a second time with more thrashing, followed by a voluntary release of the patient's hand. Control of the caiman was then gained. Scientific measurements were performed and the caiman was released. Immediate medical attention was available from an on-site physician. The patient had received a crush injury to the hand, as well as 12 puncture or tearing skin wounds to the fingers. All the wounds were smaller than 1 cm in length with the exception of a longer tear to the lateral portion of the forth digit. Clinically, the patient was neurovascularly intact but had a significant amount of pain. Tendon function was normal. Several punctures were at joint lines. Because of pain, evaluation for bony injuries was difficult; however, no obvious bone or ligament injury was seen. No radiographs could be performed secondary to the remote location of the group. The patient was taken to base camp, which was a riverboat, for further treatment. Persistent bleeding continued from the fourth digit injury. A wedding band was present on this finger. Ring removal was difficult because of fairly immediate swelling and pain. A digital block was performed and the ring was removed. The large wound was explored and irrigated with 2 L of sterile water and then loosely approximated with 4-0 Prolene with simple interrupted sutures. Loose approximation was deemed necessary because of the large size of the wound. Bleeding then stopped. All other wounds were irrigated and explored. No foreign bodies were found. The patient was started on moxifloxacin hydrochloride 400 mg orally per day. Bacitracin Zinc-Neosporin sulfate-Polymyxin B sulfate topical antibiotic ointment was applied in addition to bandages. Oral acetaminophen and oxycodone were also dispensed for pain control. The patient's tetanus immunization was up-to-date. Initially, no immobilization was used because of patient preference secondary to work activities. The patient was given instructions regarding limiting use, wound care, and daily re-exams with a group physician. Within 12 hours, the patient was experiencing increasing pain and edema. On exam, he had considerable edema and erythema to all the digits of the left hand. Range of motion was greatly limited because of pain and swelling. Most notable was the proximal interphalangeal joint of the third finger. No abnormal drainage was seen from any of the wounds. The patient's hand and wrist were immobilized in a short arm volar splint. During the following days he had persistent pain, edema, and erythema, which gradually decreased (Figure 2

). He did not develop any fever,

drainage, or lymph node swelling. On day 5, he reached an airport and began travel home. After arrival to the United States, he saw a hand surgeon on day 8. The patient was found to have an intra-articular fracture of the distal portion of the proximal phalanx of the third digit. No fracture was seen at the site of the large, partially closed laceration of the fourth digit. His pain and swelling had decreased, and he completed a 14-day course of the moxifloxacin hydrochloride. At 5 months postinjury, he has continuing problems with the use of this digit and is considering surgical repair secondary to decreased range of motion of the third digit of his left hand.

Discussion Return to Top Caimans are found throughout lowland, wetland, and river habitats of Central America and South America. C crocodilus has the widest distribution of any of the Alligatoridae. The endangered black caiman (Melanosuchus niger) and several subspecies of caimans share the same habitat. As adults, male C crocodilus are relatively small to medium sized, ranging from 2 to 3 m in length; adult females are slightly smaller. Adult caimans range from 1.5 m in the dwarf caiman (Paleosuchus palpebrosus) to 6 m in the black caiman. The common name

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(spectacled caiman) refers to a bony ridge between the front eyes that gives the appearance of spectacles. Dentition includes a range of 68 to 86 teeth. Teeth are often lost during feeding and are replaced. Caimans are aggressive hunters but tend to avoid human contact. Their carnivorous diet ranges from fish and invertebrates to large mammals and reptiles. Females are sexually mature at 1.2 m and between 4 and 7 years. They lay 14 to 40 eggs during the wet season of May to August and aggressively protect their nests from anything that approaches until hatching at near 90 days. Very little literature regarding caiman bites or attacks is available, especially from Central America and South America. More information is available about Alligator mississippiensis from studies in the southern United States.3–5,8 Information is also available about crocodiles from Australian and African studies.6,8 Two studies that specifically discuss black caimans concentrate on the description of the attack and are limited in any clinical information.11,12 Prompt and aggressive wound care is important for all bite wounds. Initial treatment should include providing a safe environment for the patient and care providers. Local wound care and immobilization at the scene should be followed by medical care. Care should include recognition of all injuries and appreciation for possible unseen problems. Exploration and radiographs for foreign bodies are paramount. Treatment should include tetanus prophylaxis and thorough wound irrigation and debridement. For most wounds, healing gradually by secondary intention or delayed primary closure will decrease incidence of infection. Some studies suggest wound culture,4,7 though this may apply more to obviously infected wounds. Little is published on the bacterial content of caiman bites; however, there is information about bites and oral flora of A mississippiensis: bacteria are predominately gram negative, and organisms include Aeromonas hydrophila, Proteus vulgaris, Pseudomonas, and Clostridium.3–6,8 If the flora is similar for caimans, it would be logical to treat with broad-spectrum antibiotics with good gram-negative coverage such as quinolones, third-generation cephalosporins, or antipseudomonal penicillins.

Conclusions Return to Top This case demonstrates the need for proper care of a patient after sustaining a caiman bite. A high level of suspicion for deep injuries and infection should be maintained. Certainly, caiman bites and attacks may be very similar to those of alligators and crocodiles, but little literature is available for the former. Additional studies would be required to determine if the oral flora, bite severity, incidence of infection, and frequency of attacks are different for caimans from other members of the family Crocodylidae. Educational points for potential victims would include avoiding nests especially during the wet season, avoiding handling or cornering caimans without proper experience and equipment, and seeking immediate medical attention for all bites. Most crocodilians, if given the chance, would choose to avoid humans. However, because of increasing human populations and an ever-widening ecological footprint, humans do not always give them that chance. In certain areas some types of crocodiles and alligators are considered nuisance animals and have to be destroyed or removed.

References Return to Top 1. Britton A., Caiman crocodilus. Available at: www.flmnh.ufl.edu/natsci/herpetology/brittoncrocs/csp_ccro.htm. 71

Accessed May 24, 2005. 2. Woodward AR, Cook B., Nuisance-alligator (Alligator mississippiensis) control in Florida, USA. Crocodiles. Proceedings of the 15th Working Meeting of the Crocodile Specialist Group, Veradero, Cuba, January 17–20, 2000. IUCN—The World Conservation Union. Gland, Switzerland; 2000:446–455. 3. Burgess GH, Callahan MT, Howard RJ. Sharks, alligators, barracudas and other biting animals in Florida waters. J Fla Med Assoc. 1997;84:428–432. 4. Flandry F, Lisecki EJ, Domingue GJ, Nichols RL, Greer DL, Haddad RJ. Initial antibiotic therapy for alligator bites: characterization of the oral flora of Alligator mississippiensis. South Med J. 1989;82:262–266. 5. Howard RJ, Burgess GH. Surgical hazards posed by marine and freshwater animals in Florida. Am J Surg. 1993;166:563–567. 6. Langley RL. Alligator attacks on humans in the United States. Wilderness Environ Med. 2005;3:119–124. 7. Meskisic AP, Wardill JR. Crocodile attacks in the Northern Territory of Australia. Med J Aust. 1992;157:715–754. 8. Raynor AC, Bingham HG, Caffee HH, Dell P. Alligator bites and related infections. J Fla Med Assoc. 1983;70:107–110. 9. Vanwersch K. Crocodile bite injury in Southern Malawi. Trop Doct. 1998;28:221–222. 10. Caldicott DG, Croser D, Manolis C, Webb G, Britton A. Crocodile attack in Australia: an analysis of its incidence and review of the pathology and management of crocodilian attacks in general. Wilderness Environ Med. 2005;16:143–159. 11. Evans P, Wilkinson P. Black caiman attack. Crocodile Specialist Group Newsletter. 1997;16:35–6. 12. Hall PM. Dangerous to man? A record of an attack by a black caiman in Guyana. Herp Rev. 1991;22:9–11.

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关于 Population genetic analysis of Caiman crocodilus (Linnaeus, 1758) from South Ame 的问题 •

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关于 Population genetic analysis of Caiman crocodilus (Linnaeus, 1758) from South Ame 的原因,关于 Population genetic analysis of Caiman crocodilus (Linnaeus, 1758) from South Ame 的相关知识。 ABSTRACT

The genetic structure of Caiman crocodilus was investigated using a 1085 bp mtDNA fragment of the cytochrome b gene. Inferences were based on 125 individuals from nine localities in Peru, Brazil and French Guiana. With the exception of Mamirauá Lake, Anavilhanas Archipelago and the Tapará Community which show a signal of demographic expansion, the sampled localities are in a mutation-drift genetic equilibrium. Divergence between the Amazon basin and extra-Amazon basin localities is significant; however, inference from Nested Clade Analysis cannot distinguish between continuous range expansion, long distance colonization or past fragmentation; however, past fragmentation is unlikely due to low number of mutational steps separating these two regions. The divergence is probably maintained by the reduced ability of C. crocodilus to cross salt water barriers. Within the Amazon basin, continuous range expansion without isolation-by-distance is the most likely process causing genetic structuring. The observed genetic patterns are compatible with the ecology of C. crocodilus, and history of human exploitation. As commercial hunting depleted more valuable species, C. crocodilus expanded its range and ecological niche, prompting hunters to harvest it. Following a period of intense hunting, C. crocodilus is now experiencing recovery and a second population expansion especially in protected areas.

Key words: genetic structure, phylogeography, genetic diversity, demographic expansion, cytochrome b, Caiman crocodilus.

Introduction

The study of spatial and temporal distribution of intraspecific genetic variability is one of the principal foci of molecular ecology. They provide important data that shed light on evolutionary processes and spatio-temporal dynamics of often complex natural populations of the Neotropics. It is these evolutionary processes that allow species to adapt to dynamically changing environments that should be conserved (Smith et al., 1997; Smith et al., 2001). Therefore, molecular ecological studies can provide vital information for the conservation and management of biological diversity.

Brazil, and in particular Amaz?nia, is rich in biodiversity (Myers et al., 2000). Of the seven alligatorid crocodilians (family Alligatoridae), five to six species occur in Brazil and four to five of those occur in Amaz?nia. The Brazilian species are classified in the genera Caiman, Melanosuchus and Paleosuchus. Melanosuchus is restricted to the Amazon, Essequibo and Oiapoque basins, while Paleosuchus is also found in the Orinoco basin and coastal drainages of The Guianas and the littoral of Brazil. Caiman has a much wider distribution, and is found from southern Mexico to northern Argentina, including all major South American drainages. Caiman crocodilus (the spectacled caiman) can reach 2.5 m of total body length. Females reach sexual maturity at three to four years of age (Staton and Dixon, 1977), the same age as Alligator mississipiensis, which is much less than the average age of nine years at female sexual maturity found in other crocodilian species (Brisbin Jr., 1988).

The taxonomy of Caiman is not firmly established, but most recent taxonomic studies recognize the species C.

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crocodilus, C. yacare and C. latirostris (Busack and Pandya, 2001). Caiman latirostris is found in the Paraná and S?o Francisco River basins, and C. yacare maily occurs in the Pantanal and Bolivian basins but also extends along the Madeira River into the Amazon basin. Caiman crocodilus is the most widely distributed species, found from southern Mexico south to the Amazon River basin (Ross, 1998). Caiman crocodilus has been classified into three subspecies in addition to the nominal subspecies. However, the only analysis that investigated morphological differentiation among regions of occurrence, and thus the validity of these subspecies, failed to show any consistent differences among the subspecies, rejecting their validity (Busack and Pandya, 2001). Caiman yacare, which sometimes is included as a subspecies of C. crocodilus, was significantly differentiated from C. crocodilus at a series of morphological and morphometric traits (Busack and Pandya, 2001).

Populations of C. crocodilus became severely threatened by the hide trade between 1960 and 1969, when more than 1.5 million skins were exported legally from the Brazilian Amazon (Smith, 1980). Harvest started focusing on C. crocodilus when commercially more desirable species, such as Melanosuchus niger, became too severely depleted to be harvested profitably. A little more than two decades thereafter, in studies conducted between 1993 and 1996 in the Jaú National Park, Rebêlo and Lugli (2001) found little demographic evidence of past overexploitation. The authors attributed the apparent well being of C. crocodilus in this area to a demographic recovery from past overexploitation. A pattern of demographic recovery is also observed in other regions of Amaz?nia (George Rebêlo personal communication).

Little is known about population genetic structuring and gene-flow patterns of C. crocodilus. Up to now, the only population genetic study is that of Farias et al. (2004) which investigated C. crocodilus from two localities in Brazil (Piaga?u-Purus Reserve and Janauacá Lake) and one locality in French Guiana (Approuague River). The authors found a signal of population expansion and high levels of genetic polymorphism in all three populations. They also found significant genetic differentiation between French Guiana and Brazil. However, the sampling scheme of Farias et al. (2004) was inadequate to discriminate among alternative historical processes underlying the observed differentiation between French Guiana and Brazil. It was also unable to test the hypothesis of panmixia within the Amazon basin.

The objective of this study was to quantify genetic variability and its spatial distribution in C. crocodilus. We used these patterns to test two specific hypotheses: 1) have C. crocodilus populations experienced a demographic and genetic recovery, as hypothesized by Rebêlo and Lugli (2001) and Farias et al. (2004); and 2) does C. crocodilus of the Amazon basin form a panmictic population, as alluded to in Farias et al. (2004) and observed in other large Amazonian vertebrates (Cantanhede et al., 2005; Hrbek et al., 2005).

Materials and Methods

Samples

Samples of caudal scutes were collected from 125 individuals at nine localities during the years 2002, 2003 and 2004. The nine localities were: Approuague River (Kaw Swamps N.R.) in French Guiana; Ua?á River (A.I. Ua?á) in Amapá State, Brazil; S?o Miguel Island and the Tapará Community in Pará State, Brazil; the Anavilhanas Archipelago (E.E. Anavilhanas), Janauacá Lake, lower Purus River (Piaga?u-Purus RDS) and Mamirauá Lake

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(Mamirauá RDS) in Amazonas State, Brazil; and Pacaya-Samíria National Reserve in Peru (Figure 1). The majority of the samples was collected at night, and samples were preserved in 95% ethanol at ambient temperature until being processed in the laboratory.

Laboratory protocol

Total genomic DNA was extracted using a standard phenol/chloroform method and precipitated with 70% ethanol (Sambrook et al., 1989). The mitochondrial cytochrome b gene was amplified via Polymerase Chain Reaction (PCR) using the primers L14254 (5’-ATGACCCACCAACTACG AAAAT-3’) from Glenn et al. (2002) and H15982 (5’-TCC CTRGCTTTGGTAGCCAGG-3’) from Farias et al. (2004).

PCR reactions were carried out in a final volume of 25 mL and contained 11.7 mL of ddH2O, 3 mL of MgCl2 (25mM), 2.5 mL of dNTPs (10 mM), 2.5 mL of 10x buffer (100 mM Tris-HCl, 500 mM KCl), 2 mL of each primer (2 mM), 0.3 mL of Taq DNA Polymerase (5 U/mL) and 1 mL of DNA (concentration varied between 50 ng and 100 ng). PCR conditions were as follows: denaturation at 92 °C for 35 s, primer annealing at 55 °C for 35 s, and primer extension at 72 °C for 90 s; these three steps were repeated 35 times, and followed by a final extension at 72 °C for 5 min. Purification of products was done using the GFXTM PCR DNA Kit (Amersham Bioscience, S?o Paulo) following the manufacturer’s protocol.

Purified PCR products were sequenced directly. Each reaction contained 4 mL of amplified DNA product (~ 30 ng), 2 mL of primer (L14254 for the 5’ segment of the amplified DNA fragment, and L14731 (5’-TCGTGCCAT GAATTTGAG-3’) from Glenn et al. (2002) as an internal primer for the 3’ portion of our DNA fragment), 2 mL of 5x replacement buffer (400 mM Tris-HCl pH 9.0, 10 mM MgCl2) and 2 mL of DYEnamic ET Dye Terminator mix (Amersham Bioscience, S?o Paulo). Cycle sequencing PCR conditions were as follows: denaturation at 93 °C for 15 s, primer annealing at 50 °C for 35 s, and primer extension at 60 °C for 120 s; these three steps were repeated 35 times. Resulting fluorescently labeled product was precipitated using a mixture of 70% ethanol and 175 mM ammonium acetate. Precipitated DNA product was resuspended in Hi-Di Formamide, and resolved on a MegaBACE 1000 automatic DNA analysis system (Amersham Bioscience, S?o Paulo) using the manufacturer’s recommended settings.

Data verification

Identity of the 125 DNA products was verified by comparing the data with cytochrome b sequences of Alligator mississippiensis (AF318548-AF318557) (Glenn et al., 2002), Melanosuchus niger and Caiman crocodilus (AY462456-AY462487) (Farias et al., 2004), and C. crocodilus (NC002744) (Janke et al., 2001) deposited in GenBank. Sequences were aligned by eye in the program BioEdit (Hall, 1999), and conceptually translated into amino acids. The 1085 bp alignment did not show insertions or deletions, and translation produced no unexpected stop codons.

Intraspecific analytical methods

Relative contributions of historical and ongoing processes are not easy to distinguish, thus various strategies

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have been proposed (Templeton et al., 1987; Bernatchez, 2001). In this study we used the Nested Clade Analysis (NCA) developed by Templeton and colleagues (Templeton and Sing, 1993; Templeton et al., 1995; Templeton, 2001; 2004). The program TCS 1.18 (Clement et al., 2000) was used for haplotype network estimation following the cladogram estimation rules laid out in Templeton et al. (1992) and elaborated in Templeton (1998; 2004). The program Geodis 2.0 (Posada et al., 2000) was used to test significant changes in haplotype and nested clade geographic distribution relative to other haplotypes and nested clades within their higher-level nesting clades (Templeton et al., 1995). The program PAUP* 4.0b10 (Swofford, 2002) was used to estimate a Neighbor Joining tree based on FST values.

The number of segregating sites between sequences (S), Nei’s (1987) nucleotide diversity (p), Nei’s (1987) gene diversity (), and Watterson’s (1975) theta (q) were calculated using the programs Arlequin ver. 2000 (Schneider et al., 2000) and DnaSP (Rozas et al., 2003). These programs were also used to compute pair-wise FST statistics (Weir and Cockerham, 1984), Analysis of Molecular Variance (AMOVA) (Excoffier et al., 1992), and tests of selective neutrality of Fu (1997) and Tajima (1989). Fu’s Fs is in general more powerful than the test of Tajima in detecting demographic events.

Wright’s inbreeding coefficient (F), the classic population genetic measure, was used to characterize intrapopulational variation and differentiation between populations. We used the method of Cockerham and Weir (1993) to estimate FST. Statistical significance of F values was estimated using bootstrapping implemented in Arlequin 2000 (Schneider et al., 2000), and adjusted using the method of Bonferroni for multiple comparison (Rice, 1989). We tested the hypothesis of isolation by distance using the Mantel test (Mantel, 1967) implemented in the program Arlequin ver. 2000 (Schneider et al., 2000), estimating the significance of correlation between matrix of ln FST values and between-locality river distances with 10000 permutations.

Analysis of Molecular Variance (AMOVA) (Excoffier et al., 1992) tests if molecular variation is non-randomly distributed among user-defined or natural groups. In this study we used AMOVA to test two hypotheses: 1) that samples from the Amazon basin do not have a significantly different genetic composition from samples originating in the non-Amazonian Atlantic Ocean drainage systems, and 2) that sampling localities from the Amazon basin are not genetically differentiated from each other. Both test the null hypothesis of panmixia, however, at different hierarchical levels. Inferences from AMOVA were confirmed by Raymond and Rousset’s test of exact population differentiation (Raymond and Rousset, 1995).

Results

We sequenced 1085 base pairs (bp) of the mitochondrial cytochrome b gene in 125 individuals sampled from nine localities (Figure 1). We found a total of 38 haplotypes (Tables 1 and 2) that included one common haplotype; this haplotype (H1) is the most frequent one and is widely distributed, two characteristics that are representative of a most likely ancestral haplotype (Castelloe and Templeton, 1994). The conceptual translation of the 1085 bp fragment in the program BioEdit (Hall, 1999) resulted in a sequence of 361 amino acids without unexpected stop codons, confirming that we have not amplified and sequenced nuclear pseudogenes. We also found an incomplete stop codon at the end of cytochrome b characteristic of crocodilians (Glenn et al., 2002). A characteristic mtDNA anti-G bias (Zhang and Hewitt, 1996) was observed in all sequences. Haplotypes are deposited in GenBank under

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the accession numbers DQ246626 to DQ246663.

In the NCA (Templeton et al., 1995) we encountered two levels at which we could not reject the null hypothesis of no association of geographic distance and distribution of genetic diversity. Nesting scheme and significant levels are shown in Figure 2. Using the 14 July 2004 NCA interpretational key (see http://darwin.uvigo.es/software/geodis. html), we inferred continuous range expansion, long distance colonization or past fragmentation in nesting level 3-1 (Table 3). This inference pertains to the contrast between sampling localities from the Amazon basin and those outside the Amazon basin. For localities from within the Amazon basin we infer continuous range expansion at level 2-2 (Table 3).

Hierarchical AMOVA analysis (Excoffier et al., 1992) implemented in the program Arlequin ver. 2000 (Schneider et al., 2000) was used to investigate differentiation between the sampling localities of the Amazon basin and those of the Atlantic coast drainages. Results show that 35.30% of variation occurs between the two groups, 6.97% occurs among localities within the two groups, and 57.73% occurs within sampling localities. The genetic difference between the Amazon basin and the Atlantic coast drainages is significant (FCT = 0.3530, p = 0.023), and is graphically illustrated in Figure 3.

A second AMOVA analysis concentrated exclusively on the Amazon basin. When the Amazon basin was treated as one group, 8.39% of the observed genetic variation occurred between localities, and 91.61% within localities. However, among locality differentiation is significant (FST = 0.0839, p < 0.001). Global test of exact population differentiation (Raymond and Rousset, 1995) also supported the hypothesis of differentiation among localities (p < 0.001). We tested if this differentiation may be due to isolation-by-distance by testing for significant association of geographic distance and genetic divergence of sampled localities using the permutational procedure of Mantel (1967). Results of the Mantel test indicate that isolation-by-distance is not a significant structuring factor, neither for all populations analyzed (r = 0.4621, p = 0.058), nor for the Amazon basin only (r = 0.1036, p = 0.354). Estimates of the gene flow parameter Nm derived from FST values indicate that high levels of genetic exchange exist between nearly all sampled localities (Table 4).

Analyses of mutation-drift equilibria (Tajima, 1989; Fu, 1997) indicate that almost all sampled localities are in a genetic equilibrium (Table 5). Only for the Anavilhanas Archipelago, the Mamirauá Lake and the Tapará Community does Fu’s Fs test show a significant genetic disequilibrium. However, when the Amazon basin is treated as one large population, both statistics indicate a significant genetic disequilibrium (Tajima’s D = -2.548, p < 0.0001; Fu’s Fs = -30.965, p < 0.0001).

Discussion

Cytochrome b polymorphism and genetic equilibria tests

Gene diversity encountered in the present study was high ( = 0.733; 1085 bp), and comparable to the values ( = 0.692; 1142 bp) found in the study of Farias et al. (2004). These values are much higher than the value observed for Alligator mississippiensis ( = 0.153; 1317 bp) by Glenn et al. (2002). These values indicate that Caiman crocodilus populations retain high levels of genetic diversity in spite of historical events which reduced its

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population size. Neither the hypothesized climatic changes in the Amazon basin (Ab’Saber, 1977), nor recent commercial overexploitation (Smith, 1980; Da Silveira and Thorbjarnarson, 1999) appear to have affected the gene diversity of C. crocodilus populations. In contrast to C. crocodilus, the only other alligatorid crocodilian for which a comparable data set has been generated, the American alligator A. mississippiensis, shows much lower gene diversity (Glenn et al., 2002). This low gene diversity was attributed by the authors to severe reduction in population size during the Pleistocene, with a subsequent demographic expansion in the Holocene, but not to commercial overexploitation that also significantly reduced the census numbers of this species.

Of the nine localities studied, three (Table 5) show a significantly negative value for Fu’s Fs test. Although this test was formally designed to test for selection, in the absence of selective advantage among haplotypes, a significant negative deviation from genetic equilibrium in mtDNA alleles is most probably the result of recent population expansion (Rand, 1996; Hartl and Clark, 1997). Fu’s Fs statistic is more sensitive to demographic events than is Tajima’s D (Rand, 1996). Thus, the inference drawn from our analyses suggests that while the Anavilhanas and Mamirauá localities - both of which are strictly protected at the federal and state level, respectively - and the Tapará locality have experienced a recent population expansion, this expansion was not very strong, and has been registered only by the most sensitive statistic. Some areas, however, show very little genetic evidence of population expansion, or of census number increase. These areas include the Pacaya-Samíria National Reserve (BM, pers. obs.) and the Ua?á Indigenous Area (Ruffeil, 2004) where C. crocodilus remains a popular food item, and is harvested in significant numbers. When all sampled localities are analyzed as one population, both Tajima’s D and Fu’s Fs statistics are significantly negative. This result suggests an overall population expansion of this species that also has been registered as growth in census numbers (Rebêlo and Lugli, 2001). Again, the signal is not very strong and is only observed when the statistical power of the tests is increased by analyzing all samples together.

The genetic signal of overall population expansion is compatible with historical data and current observations. Caiman crocodilus is a habitat generalist. It also has been much less affected by the commercial trade than other sympatrically occurring species, such as Melanosuchus niger, Crocodilus intermedius or Crocodilus acutus, being harvested in large numbers only after these latter species became too severely depleted to support commercial operations. Because of the lack of ecological specialization (Herron, 1994), C. crocodilus was able to expand into habitats previously occupied by sympatrically occurring species (Da Silveira et al., 1997). Even when commercial hunters started harvesting the then plentiful C. crocodilus and precipitated its demographic decline, the present population is probably larger than were historical populations, which had to co-exist with large numbers of well established crocodilian species (Ross, 1998). Caiman crocodilus also has, once again, expanded following global and local harvest moratoria and regulations, experiencing two cycles of recent expansion, with an intervening period of decline, and it is this second expansion we are observing in the current pattern of genetic diversity.

Inference of population genetic structure

A minimum-spanning haplotype network was nested into higher level nesting categories (Templeton et al., 1992) and analyzed for non-random distribution of genetic diversity over geographic space (Templeton et al., 1995). The Nested Clade Analysis (NCA) allows identification of population genetic structure and the discrimination of various historical and ongoing processes responsible for the current pattern of genetic

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structuring. Its greatest power lies in that it requires no a priori hypothesis of population structure. Once patterns are observed, they can then be tested further.

Using the NCA approach we observed two hierarchical levels which have a significantly non-random distribution of genetic diversity. Inferences from level 3-1 suggest that the main populational dynamics responsible for the observed genetic differentiation of the Atlantic drainage systems not connected to the Amazon basin and Amazon basin localities are continuous range expansion, long distance colonization, or past fragmentation. However, past fragmentation is not very likely due to the small number of mutational steps separating the Ua?á and Approuague Rivers haplotypes from haplotypes found in the Amazon basin. When only the Amazon basin is analyzed, the inference at level 2-2 is continuous range expansion. Thus, continuous range expansion is likely to be the main dynamic within the Amazon basin, but due to insufficient sampling, we cannot differentiate between continuous range expansion or long distance colonization as the main populational dynamic responsible for the observed genetic differentiation between the Atlantic drainages not connected to the Amazon basin and Amazon basin sampling localities. Analysis of Molecular Variance (Excoffier et al., 1992), as well as pair-wise FST values also support the inference that the Ua?á and Approuague Rivers are significantly differentiated from localities of the Amazon basin.

A possible factor that could have contributed to this distribution of genetic diversity is the present day distribution of river basins relative to their paleogeographic positions. The direction of the inferred colonization or range expansion is from the Amazon basin into the coastal drainages of French Guiana and Amapá State of Brazil. This could have occurred during the last Pleistocene glacial maximum when sea levels were up to 200 m lower than present. The Amazon delta extended much further east than its present position, and many of the now isolated coastal drainages were connected to the Amazon basin via the delta of the Amazon River. This would have facilitated dispersal and colonization of new areas, now outside the Amazon basin, during the glacial maximum. Modern alligators are less tolerant to salt water than other crocodilians since they posses neither a tongue gland in their mouth cavities that excretes salt, nor a reno-cloacal complex adapted for the excretion of salt and conservation of fresh water (Taplin and Grigg, 1989). For this reason, salt water is considered a major barrier to dispersal of Alligatoridae (Brochu, 2001), and it is unlikely they would have colonized the French Guiana and Amapá coastal drainages recently.

NCA analyses within the Amazon basin indicate that continuous range expansion is the most likely processes responsible for the observed distribution pattern of genetic diversity. Both AMOVA and Raymond and Rousset’s test of exact population differentiation reject the hypothesis of panmixia; however, the distribution of genetic diversity is not compatible with the model of isolation-by-distance. In spatial autocorrelation analysis (Koenig, 1999; Diniz-Filho and Telles, 2002) which tests the hypothesis of isolation-by-distance, geographic distances are partitioned into classes of connectivity or lack thereof at ever increasing distances. The spatial autocorrelolegram predicts elevated correlation at lower distances of connectivity with eventual leveling off, a pattern not observed in our data. The observed structure is therefore most likely the result of genetic subsampling of parental populations during periods of range expansion. However, range expansion did not proceed in a linear manner. Range expansion possibly proceeded locally as commercially more valuable species were being locally depleted by commercial hunters, and the resulting ecological space was being filled by an expanding C. crocodilus population. Alternatively, we may be observing a signature of coalescent processes in a species distributed over a large

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geographic area, thus a historical record rather than an ongoing process.

Another pattern which contributes to the rejection of panmixia within the Amazon basin is the significant differentiation of the Anavilhanas locality from all but the geographically closest Mamirauá Lake, Purus River and Janauacá Lake localities. The locality from the Anavilhanas archipelago is the only one sampled from a black water system (Sioli, 1984). Black water systems are limnologically and ecologically differentiated from white water systems, often supporting different animal and plant communities (Sioli, 1984; Goulding et al., 2003). There are a number of black water systems in the Amazon basin, but the Negro River is the largest. The observed differentiation of the Anavilhanas locality corroborates, in principle, the findings of Farias et al. (2004). Although Farias et al. (2004) did not include C. crocodilus from Anavilhanas in their analyses, they observed weak genetic differentiation between black water (Anavilhanas) and white water (rest of the Amazon basin) sampling localities of Melanosuchus niger, the other large alligatorid crocodilian found in Amaz?nia. Ecological differences between caiman populations occupying black water and white water habitats were also observed by Da Silveira (2002). Together, these genetic and ecological findings suggest that the observed black water / white water differentiation might be a real geographic structuring factor in Amaz?nia that reduces genetic exchange between limnologically differentiated systems. The two other significant pair-wise FST comparisons observed within Amaz?nia occur between geographically distant localities.

The lack of pattern of genetic structuring among localities within the Amazon basin contrasts with the study of Verdade et al. (2002) who studied five geographically proximate populations of Caiman latirostris from the state of S?o Paulo. Based on an analysis of four microsatellite loci, Verdade et al. (2002) observed significant correlation between geographic and genetic distance. The habitat occupied by these populations is fragmented, which, combined with high mortality and low birth rates, should result in a low number of successfully dispersing individuals per generation leading to the pattern of isolation-by-distance (Verdade et al., 2002). The fragmented and discontinuous habitat occupied by C. latirostris contrasts with what is essentially a continuous habitat of the Amazon basin available to C. crocodilus. Nevertheless, the fragmented populations of C. latirostris outside the core continuous habitat of the Pantanal basin show a certain degree of differentiation, which is a classic pattern of peripatric differentiation observed in diverse taxa (Mayr 1963).

Acknowledgments

We would like to thank Sociedade Civil Mamirauá, The Mamirauá Institute, The Wildlife Conservation Society, The Nature Conservancy of Brazil and FAPEAM (Funda??o de Amparo a Pesquisa no Estado do Amazonas) for financial support, RAN/IBAMA for permission to conduct field work, and CGEN/IBAMA for permission to conduct laboratory work. Renato Da Silveira, Pedro Alexandre Sampaio, Eduardo Matheus von Muhlen, Augusto Ruffeil and Marcelo Crossa helped in the field, and Richard Bodmer facilitated fieldwork in Peru, and the comments of two anonymous reviewers improved this publication.

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.::::: Crocodiles of the World - Caiman :::::.

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Last update: 23 May, 2004

Estado Actual y Perspectivas del Caimán  Negro (

Melanosuchus niger ), con Énfasis  en la Amazonía Colombiana  Año 2002 Volumen III Número 3

BRIEVA, Claudia 3

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R ESUMEN El caimán negro (Melanosuchus niger), habita exclusivamente la región de la cuenca amazónica de América del Sur. Es un reptil del orden Crocodylia, familia Alligatoridae, caracterizado por ser el mayor crocodílido del neotrópico,  llegando a alcanzar una longitud de 6 metros. Prefiere habitar en lugares de aguas quietas y tranquilas.  El caimán negro fue muy abundante en el pasado, pero debido a la cacería indiscriminada e incontrolada a la que fue sometido durante las décadas de 1.950 y 1.960, sus poblaciones llegaron casi a la total extinción. Actualmente se hallan algunos reductos en áreas alejadas y poco perturbadas, pero en general la situación de la especie es tan crítica que figura en el apéndice I del CITES.  Las instituciones nacionales e internacionales son concientes de la necesidad de conservar la especie para lograr poblaciones estables, susceptibles de explotar racionalmente. El primer paso para ello es realizar un diagnóstico acerca del estado actual de las poblaciones libres, para posteriormente formular planes de manejo y conservación, los  cuales deben basarse principalmente en la conservación de los ecosistemas que albergan la especie.  3

Directora URRAS. Médica Veterinaria. Universidad Nacional de Colombia, Bogotá – Colombia . Correo electrónico: [email protected]

Page 2 ESTADO ACTUAL Y PERSPECTIVAS DEL CAIMÁN NEGRO (

Melanosuchus niger ), CON ÉNFASIS EN LA AMAZONIA COLOMBIANA 28 / 2002 VOLUMEN III: 3 

A BSTRACT The black caiman (Melanosuchus niger), inhabits only in the Amazonian region of South America. It is a reptile of the order Crocodylia, family Alligatoridae, the biggest crocodile of the neotropics, with 6 meters of lenght. It prefers quiet waters to live.  The black caiman was abundant in the past, but due to the indiscriminated hunting during the decades of 1.950 and 1.960, its populations are almost in complete extinction. Actually there are some reducts in distant an nondisturbed areas, but in general the situation of this species is very critical, therefore it is in the appendix I of the CITES. 

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The national and international institutions are conscious about the need of preservation of the black caiman to obtain  steady populations, for the reasonable usage. The first step to obtain this purpose is the diagnosis about the present status of free populations, to make further management and conservation programs. These programs will be based in the preservation of ecosistems that contains this species. 

I NTRODUCCIÓN Dentro del orden Crocodylia se encuentran muchas especies que han sido tradicionalmente utilizadas por los  habitantes de las zonas neotropicales para su alimentación y para la elaboración de artículos de cuero. Este hecho ha llevado a que casi la totalidad de poblaciones de crocodílidos en el mundo se encuentren amenazadas por la cacería indiscriminada y sin control, que se inició en la primera mitad de este siglo, con el fin de abastecer los mercados mundiales de los artículos elaborados en cuero. Otro factor que ha incidido en la acelerada disminución de las  poblaciones es la destrucción de los ecosistemas que habitan. La situación descrita ha llevado a muchas instituciones  nacionales e internacionales a interesarse en los crocodílidos, tomando conciencia de la necesidad de formular planes  de manejo y conservación del recurso. Como una contribución a este propósito, se llevó a cabo un trabajo de revisión bibliográfica y análisis del estado actual y perspectivas de una de las especies de crocodílidos colombianos más  amenazada y menos estudiada: el caimán negro (Melanosuchus niger). 

C ARACTERÍSTICAS 

G ENERALES Melanosuchus niger (Spix, 1.825).  Nombres comunes: Caimán negro, black caiman, lagarto negro, jacaré açu.  Es la especie más grande de crocodílido del Nuevo Mundo; se han reportado ejemplares que sobrepasan los 6 metros de longitud. La especie antiguamente se extendía por toda la región amazónica, desde la desembocadura del río Amazonas en el oriente, hasta Ecuador, en el occidente. Los hábitats preferidos por la especie incluyen los ríos quietos de aguas estancadas, lagunas, bosque inundable y gramalotales. (Webb y col, 1.987; Da Silveira, 1.993)  Para la clasificación taxonómica, Medem (1.983) emplea características externas morfológicas. El M. niger se caracteriza por poseer un cráneo ancho pero no corto, con una arista interorbital y un par de aristas maxilares 

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longitudinales elevadas. El vómer es visible tanto en juveniles como en adultos. Distribución en Colombia: Según Medem (1983), la especie se encontraba en todo el Trapecio Amazónico. Ocupaba igualmente el Putumayo, hasta Caño Concepción, y el Bajo y Medio Caquetá, con sus afluentes Cahuinarí y Mirití ­ Paraná. En 1.943 se hicieron ensayos para introducir la especie (25 ejemplares juveniles) en el Alto Caquetá, pero no prosperaron. Alimentación: De nueve ejemplares coleccionados por Medem (1.983), cuatro tenían el estómago vacío. Los cinco  restantes presentaban restos del esqueleto de una nutria (Lutra longicaudis), restos de grillos (ortópteros), plumas  negras de ave pequeña, dos peces de escama no identificados, restos de una sardina. No se encontraron gastrolitos. Webb y colaboradores (1.987) reportan el consumo de chigüiro (Hidrochaeris hidrochaeris).  Reproducción: La época de desove comienza a fines de Noviembre y dura hasta principios de Enero. Los nidos, en forma de montículo, se encuentran en los bosques de galería, cerca a la orilla de los ríos o en sitios elevados situados en juncales que cubren parte de los terrenos pantanosos. Los nidos contienen entre 35 y 50 huevos. La  hembra se queda acostada en el nido por largo rato, al parecer para proteger los huevos de una sobreexposición a la luz solar; luego permanece cerca del nido, dispuesta a atacar a quien intente acercarse a él. Las crías nacen entre  Enero y principios de Abril. (Gorinsky, McTurk y Thompson, 1.972, citados por Medem, 1.983; Webb y col, 1.987;  Neira, 1.987) 

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Depredadores: Según indígenas de la región, el jaguar caza con frecuencia a los juveniles y subadultos que permanecen separados de los adultos en los pantanos y cerca a la orilla de las lagunas. Neil, 1.971, reporta un caso  de predación de un caimán negro adulto por una anaconda.  Vocalizaciones: Los caimanes negros, al igual que otras especies, responden a la imitación de sus vocalizaciones. Los ejemplares juveniles emiten una serie de sonidos bajos, parecidos a ladridos o gruñidos; los ejemplares grandes emiten un sonido similar a un "puje" ronco impresionante que, según el autor, hace vibrar el aire. Después de vocalizar, los adultos dan varios coletazos fuertes. En la época de celo, hay mayor emisión de vocalizaciones. Al  parecer existe un comportamiento colectivo, en el cual un grupo es estimulado por el gruñido de un individuo, y  contestan al unísono, dando coletazos. En estos hábitos, la especie difiere de los demás cocodrílidos suramericanos. 

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(Medem, 1.983; Campbell, 1.973).  Territorialidad: El M. niger es más gregario que otras especies, pero no obstante los individuos grandes ocupan un lugar en el lago o pantano, que defienden ferozmente de los invasores de la misma especie. En algunos lugares es posible observar individuos amontonados. Son menos agresivos que otras especies, pues no se observan colas  cortadas, extremidades mutiladas o cicatrices en la cabeza, comunes en otras especies. Al colocarlos en compañía de individuos de otra especie, son más bien tímidos y asustadizos. (Medem, 1.983). 

E STADO DE LAS 

P OBLACIONES El caimán negro fue abundante en muchas áreas durante el siglo pasado, pero ha venido siendo indiscriminadamente explotada por cazadores de pieles desde principios de la década de 1.930. Su gran tamaño y su relativa carencia de osteodermos, la colocan entre las especies preferidas para la comercialización. (Webb y col., 1.987).  Según Medem (1.983), a principios de la década de los 50 la especie era muy abundante, principalmente en el Bajo Caquetá y el Putumayo. La caza comercial empezó en el Amazonas antes de 1.945, intensificándose posteriormente.  En el Bajo Caquetá comenzó en 1.950, y al final de la década la especie era muy escasa en la zona. En 1.968, Medem no observó ningún ejemplar en el Bajo Caquetá y sus afluentes. A pesar de la protección estatal (1.968), el M. niger fue perseguido sin medida hasta principios de la década del 70. Según estadísticas oficiales y datos  obtenidos por Medem, se exportaron legalmente 41.600 pieles y 19.700 animales vivos desde Leticia, Bogotá,  Barranquilla y Cali, en 1.970.  Según reportes de Foote (1.975) y de Morales y Chiriví (INDERENA, 1.977), el M. niger había desaparecido virtualmente del territorio colombiano.  Actualmente las poblaciones de caimán negro se encuentran notablemente disminuidas a lo largo de todo su rango de distribución, y están localmente extintas o en vía de extinción. La mayor población conocida (cerca de 1.000 individuos adultos) se localiza en Kaw (Guyana Francesa). Otras poblaciones abundantes se localizan al este de  Ecuador (Limón Cocha) y en el Parque Nacional Manú, en el Perú. (Webb y col., 1.987).  En el censo realizado por Barahona, Bonilla, Martínez y Naranjo (1.996), se obtuvieron los siguientes resultados, con relación al estado actual de las poblaciones de M. niger en Colombia: 

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Durante el censo se contaron 217 ejemplares en los ríos Putumayo, Curilla y Caucayá, y en las lagunas La Apaya,  Yarinas y Sunicocha; se hallaron 4 animales en el sector superior del río Caquetá, pero no en el sector inferior ni en  los ríos Caguán y Apaporis. En la cuenca del Amazonas se encontraron 51 individuos (ríos Amazonas, Loretoyacu y  Boiahuasú, y en los lagos El Socó, Tarapoto y Garzacocha). Los núcleos con mayores valores tanto absolutos como relativos se hallan en las tres lagunas el Putumayo (76,7% de los caimanes negros censados); en el lago Garzacocha del Amazonas también se encuentra un núcleo de alta densidad. El restante 16,9% de los animales hallados se encontraron principalmente en áreas marginales de los ríos, las cuales no son el hábitat preferido por esta especie.  En cuanto a la estructura poblacional, hay una fuerte tendencia hacia el equilibrio entre clases de tamaños; esta condición indica que la población está siendo explotada. Se identificó la prevalencia hasta 1.991 de caza ilegal de cocodrílidos en el río Caquetá, donde sólo se encontraron 3 ejemplares. En las cuencas del Putumayo y el Amazonas  se identificaron procesos de colonización y aprovechamiento forestal como causas que presionan al M. niger a  desplazarse hacia zonas sin tensiones ambientales. Según los reportes mencionados, la situación actual indica una leve recuperación de las poblaciones, con concentración en áreas sin tensiones ambientales, principalmente lagunas. La explotación de la especie parece continuar, aunque probablemente responda a cacería de subsistencia y de comercialización ocasional. 

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Melanosuchus niger ), CON ÉNFASIS EN LA AMAZONIA COLOMBIANA 30 / 2002 VOLUMEN III: 3 

De acuerdo a testimonios de los pobladores de las riberas del río Amazonas (P.N.N. Amacayacu), ocasionalmente se  observan ejemplares de caimán negro en algunos lagos, aunque anteriormente eran mucho más abundantes. 

L EGISLACIÓN El Decreto 1608 de 1.978, que regula todo lo relacionado con fauna silvestre dentro del territorio colombiano, establece la sanción indefinida para la cacería y para la recolección de huevos de esta especie. En 1.973 se establece una veda total para la cacería de todas las especies de crocodílidos en Colombia.  En la Resolución 0017 de 1.987, por la cual se regula el Acuerdo 039 de 1.985, se establece el número máximo de ejemplares que podrán conformar la población parental para el establecimiento de zoocriaderos. Se mencionan 10

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ejemplares para la especie Melanosuchus niger, y se hace la salvedad de que esta especie se encuentra en peligro de extinción, por lo cual sólo se autoriza su aprovechamiento a partir de la segunda generación, una vez el  zoocriadero haya superado la etapa experimental.  El Melanosuchus niger figura en el apéndice I del CITES (especies amenazadas de extinción). Implicaciones: se  requieren permisos especiales tanto del país exportador como del importador para comerciar cualquier subproducto de las especies contempladas en la lista. 

C RÍA EN 

C AUTIVERIO Algunas experiencias de cría en cautiverio con otras especies de crocodílidos se han llevado a cabo en países como Estados Unidos, Australia, Papúa Nuava Guinea y Zimbabue. En Colombia existen experiencias principalmente en la cría de babilla (Caiman crocodilus), con resultados aparentemente satisfactorios, y se está incentivando la cría en cautividad de otras especires amenazadas, como el Crocodylus intermedius. (Ortegón y Quintero, 1.994; Lugo, 1.995; Da Rocha, 1.981).  Actualmente el caimán negro no es objeto de explotación comercial debido principalmente a las restricciones  internacionales (CITES), al estado crítico de sus poblaciones y al desconocimiento de muchos aspectos sobre biología de la especie y estado de las poblaciones libres.  Aunque parezca que no hay esperanzas para las poblaciones de cocodrilos, aún no es demasiado tarde. Con una  intervención inteligente y bajo buenas condiciones, los crocodílidos pueden llegar a recuperarse rápidamente. Los  cocodrilos maduros no tienen predadores distintos al hombre, y con el adecuado cuidado y protección, un pequeño número de reproductores pueden producir una gran cantidad de crías cada año. Las hembras maduras de varias especies de crocodílidos pueden poner entre 30 y 70 huevos por año, y bajo condiciones normales la mayoría de estos huevos llegan a eclosionar. La clave de la conservación de las poblaciones es proteger a los pocos animales  maduros en sus hábitats. Muchos países han comenzado a implementar programas de protección y cría en cautiverio (Australia, India, Zimbabue, Kenia, Papúa Nueva Guinea y Tailandia). El éxito de muchos de estos proyectos hacen  pensar que con un adecuado trabajo de protección e investigación, los crocodílidos se pueden convertir en un importante recurso para los países tropicales. Las poblaciones en su hábitat natural deben mirarse como un recurso 

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que tiene que ser manejado adecuadamente para garantizar su conservación. Esto requiere una legislación estricta, cooperación internacional e investigación, así como un cuidadosos monitoreo de la comercialización. De esta manera se contribuirá igualmente a preservar los delicados ecosistemas acuáticos que so habitados por los crocodilianos. (National Research Council, 1.993; Brazaitis; Delany, 1.987; Hines y Percival, 1.987; Pachón, 1.982). 

Crocodílidos como Animales de Granjas Los crocodílidos bien alimentados crecen rápidamente. Existe la creencia de que estos animales son comedores  voraces, pero no es cierto. Muchas especies tienen una tasa de conversión del 50% es decir, ganan 1 Kg. de peso  por cada 2 Kgs. de comida suministrado; después de dos años de crecimiento, esta tasa disminuye al 25 o 30%,  convirtiéndolos en los animales de granja más rentables, junto con algunos peces. La eficiente conversión se debe a  su reducida tasa metabólica, pues son animales muy letárgicos, y no necesitan energía para termoregulación por ser  reptiles. (National Research Council, 1.993; Hall, 1.985)  La cría de cocodrilos también es eficiente en cuestión de utilización del espacio. Cientos de juveniles y docenas de  adultos pueden colocarse en espacios pequeños. Se conoce relativamente poco acerca de las enfermedades de los  reptiles, pero éstos tienen la ventaja de que producen anticuerpos rápidamente ante infecciones externas. En vida libre es común encontrar animales mutilados o con protrusión ocular, los cuales sanan rápidamente. Por el contrario,

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las infecciones internas como la salmonelosis, pueden diezmar una población en cautiverio. (National Research Council, 1.993; IUCN, 1.989) 

Limitaciones de las Granjas de Cocodrilos Las granjas de cocodrilos no son una fuente de enriquecimiento rápido y fácil. Establecer un sistema de granjas puede tomar más de 10 años, y requiere de una gran inversión antes de obtener resultados biológicos y económicos.  Sin embargo, es vital establecer una industria organizada, pues las granjas rurales sólo son viables si existe alguien que compre y comercialice el producto con toda la documentación requerida. Igualmente se requiere asistencia técnica a todos los niveles. (National Research Council, 1.993; IUCN, 1.989)  Ross y colaboradores, identifican tres tipos de zoocriaderos:  Las granjas, establecimientos de ciclo cerrado, que solamente toman del medio reproductores para renovación

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genética de la población. Todos los ejemplares comercializados han nacido en el establecimiento. Deben demostrarle  al CITES que son capaces de producir una segunda generación viable de la especie.  Los ranchos, que toman del medio crías, adultos o huevos (rancheo), para hacer levante con fines comerciales. Hay  dos tipos de rancho: las estaciones de cría, que toman huevos y juveniles y los crían hasta obtener ejemplares de tamaños comercializables, obteniendo ingresos de la venta de pieles y ocasionalmente del turismo. El otro tipo de rancho es aquel que toma del medio animales de tamaño comercializable, además de huevos y crías; uno de sus  objetivos principales es la conservación del hábitat y de las poblaciones, para mantener un volumen constante de cosecha. Deben demostrarle al CITES que la recolección de huevos y crías no pone en peligro la supervivencia de la especie.  Los bancos, que tienen fines educativos, de conservación o de rehabilitación. Crían especies en peligro para su posterior uso en planes de repoblamiento en zonas protegidas. Reciben ingresos por turismo o por subvenciones  gubernamentales o de otras entidades. Muchos parques zoológicos están dentro de esta categoría.  Existen experiencias exitosas de zoocría en muchos países. En Estados Unidos, la región de Luisiana es pionera en cría de cocodrílidos. El más destacado es el Refugio Rockefeller, que se inició con investigaciones previas sobre las  dimensiones adecuadas de los estanques para el buen desarrollo de los caimanes, la nutrición y sus efectos en la fertilidad, el tiempo que los animales pasaban en la tierra y en el agua, y el número adecuado de machos y de hembras para una producción óptima de huevos. En este refugio se generaron metodologías para la recolección e  incubación de huevos y para la cría de juveniles con fines comerciales. Para ello se desarrollaron investigaciones  sobre la dieta de las crías, la determinación del sexo por la temperatura, las causas de malformaciones y la prevención de las enfermedades más comunes. Los métodos implantados en esta granja, modificados según las  características de cada región, se utilizan hoy en día en muchos países. (National Research Council, 1.993; King). 

C ONSERVACIÓN VERSUS 

E XPLOTACIÓN La demanda de pieles de cocodrilo se incrementa anualmente, y pasarán muchos años hasta que las granjas puedan  suplir las necesidades del mercado. El trabajo de las granjas debe complementarse con la protección de ejemplares en su medio, en reservas y parques naturales, y con la conservación de los hábitats acuáticos. Si los ecosistemas 

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naturales se destruyen, las especies de cocodrilianos y muchas otras, desaparecerán sin remedio. (National Research Council, 1.993; Fuchs y col.)  Muchos países han fallado en proteger las poblaciones silvestres por no poseer los recursos humanos y económicos suficientes, y por lo extenso y apartado de las áreas a patrullar. Así mismo, se está intentado proteger a un animal que no goza de la simpatía popular. (National Research Council, 1.993; Magnusson, 1.979)  Un ejemplo de cómo compaginare la conservación con la explotación comercial es el programa de Papúa Nueva Guinea, el cual usa la estrategia de recurrir a los pobladores locales como directos encargados de la protección del hábitat natural, pues de él derivan su sustento. De esta manera se conserva un ecosistema que alberga una gran diversidad genética y que, de otra manera, habría sido destruido. (National Research Council, 1.993; King)  Contrario a la creencia popular, observaciones preliminares indican que los cocodrilos benefician la pesquería comercial. Son parte importante de los ecosistemas de ríos y lagos, pues son los más grandes habitantes de los  ambientes de agua dulce; sus movimientos inhiben el crecimiento de plantas acuáticas en los cuerpos de agua, y, en  zonas con estación seca prolongada, algunas especies mantienen charcos de agua residual que benefician a pequeños organismos acuáticos. En estuarios y lagos, los cocodrilos enriquecen el contenido de nutrientes del agua, 

Page 6 ESTADO ACTUAL Y PERSPECTIVAS DEL CAIMÁN NEGRO (

Melanosuchus niger ), CON ÉNFASIS EN LA AMAZONIA COLOMBIANA 32 / 2002 VOLUMEN III: 3 

pues convierten las presas terrestres en heces que son consumidas por invertebrados y peces. En lugares donde los  cocodrilos han sido eliminados (Brasil, Kenia e India), se ha presentado una disminución sustancial en la pesca para consumo humano. (National Research Council, 1.993: Fittkau, 1.970) 

P ERSPECTIVAS Existen algunos estudios de prefactibilidad para el uso sostenible del caimán negro mediante la cría en cautiverio,  pero la mayoría de ellos son demasiado superficiales y dejan de lado aspectos de biología y comportamiento de la especie; además de ello trabajan toda la parte financiera sobre supuestos, pues no existe un mercado real de subproductos de caimán negro.  Para el montaje de un proyecto de explotación sostenible del caimán negro, mediante cría en confinamiento o 

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rancheo, se debe tener muy en claro que uno de los objetivos primordiales es la investigación tanto en vida libre como en cautiverio, pues se conoce muy poco sobre esta especie. No se deben crear falsas expectativas en la comunidad para tratar de difundir la zoocría de caimán negro como una alternativa de captar ingresos, pues no existen experiencias previas exitosas, y falta mucho camino en investigación y experimentación. El único renglón en el cual es factible la utilización inmediata de la especie para la captación de ingresos es el ecoturismo.  Para los aspectos técnicos de un criadero de caimán negro, puede extrapolarse información disponible para otras  especies (Caiman crocodilus, Alligator mississippiensis, Crocodylus intermedius) en cuanto a infraestructura, dieta, cuidado sanitario y manejo, sin dejar de lado la investigación de características propias de la especie. El  mantenimiento en cautiverio sin pretensiones comerciales puede llegar a ser exitoso, pues se reportan experiencias  similares en zoológicos (zoológico de Leticia, Amazonas). 

P RIORIDADES DE 

I NVESTIGACIÓN Y

M ANEJO La prioridad número uno es el monitoreo del estado actual de las poblaciones, y la identificación de sitios donde haya  poblaciones estables; dichos lugares son estratégicos para programas de conservación. Es necesario continuar con la protección legal de la especie, pues ha sido sobreexplotada y se requiere mucho tiempo para que se recuperen sus  poblaciones naturales. Otra prioridad es la protección y conservación de los ecosistemas que albergan un mayor  número de ejemplares, pues la deforestación y la contaminación atentan de manera indirecta contra el caimán negro y  hacen que se desplace a zonas marginales, inadecuadas para su supervivencia a largo plazo. Un último aspecto de importancia es la urgente necesidad de investigar sobre esta especie tanto en vida libre como en cautiverio, principalmente en aspectos relacionados con estructura poblacional, comportamiento, reproducción y ecología.  La explotación comercial del caimán negro no es posible a corto plazo, pues esta especie se encuentra en estado crítico y se desconocen muchos de sus aspectos biológicos. Otra alternativa es la combinación de zoocría y rancheo (recolección de huevos y neonatos), método que ha dado resultado en otros países en vías de desarrollo (Papúa Nueva Guinea, Zimbabue, Bangkok), pues incentiva a las poblaciones locales a conservar los hábitats que albergan a

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los crocodílidos, como fuente de suministro de huevos y neonatos, representando ingresos económicos. En otras  palabras, la conservación del ecosistema se convierte en una fuente de ingresos.  Para establecer métodos de rancheo sin que peligren las poblaciones naturales, se debe tener una idea bastante aproximada del estado de las poblaciones naturales para establecer cuotas de extracción. Para ello es necesario  implementar una serie de estudios basados en el monitoreo anual mediante la realización de censos (conteos nocturnos), como los llevados cabo en el territorio de Florida, los cuales sirvieron de base para la formulación de planes de manejo en vida libre y cautiverio de las poblaciones de Alligator mississippiensis. 

B IBLIOGRAFÍA 1. BARAHONA, S., P. BONILLA, A. MARTINEZ y H. NARANJO. 1.996. Estado, distribución, sistemática y conservación de los crocodylia colombianos Censo 1.994­1.995 Ministerio del Medio Ambiente ­ Dirección General Forestal y de Vida Silvestre ­ Subdirección de Fauna, Bogotá.  2. BRAZAITIS, P. El comercio de cocodrilos. Los cocodrilos y el hombre.  3. CAMPBELL, H. 1.973. Observation on the acoustic behaviour of crocodilians. Zoológica, New York.  4. CHIRIVI, H. 1.971. Notas sobre la problemática del manejo de los Crocodylia en Colombia con especial referencia a la babilla (Caiman crocodilus), y la factibilidad de su cría en cautividad, INDERENA, Bogotá 

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5. DA ROCHA, R y P. DE TARSO. 1.981. Reproduçao em cautiverio de Caiman latirostris (Daubin), o jacaré de papo amarelo, no jardim zoológico do Rio de Janeiro. Rev. Brasil. Biol.41(4):883­885, Noviembre. Río de Janeiro.  6. DA SILVEIRA, R. 1.993. Distribuçao, abundancia, áreas de nidificaçao e hábitos alimentares de Caiman  crocodilus crocodilus e Melanosuchus niger (Crcocodylidae / Alligatorinae) no archipélago das Anavilhanas,  Amazonia Central, Brasil. INPA ­ UFAM, Manaus.  7. DELANY, M. 1.987. What do alligators eat ?. Florida Wildlife, Nov­Dic.  8. _____________. 1.986. Bird band recovered from american alligator stomachs in Florida. North American Bird Banding 11(3), Jul ­ Sept. 

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9. _____________ y C. ABERCROMBIE. 1.986. American alligators food habits in Northcentral Florida. J. Wildl. Manage. 50(2): 348­353.  10. FITTKAU, E. 1.970. Role of the caimans in the nutrient regime of mouth lakes of Amazon affluents (an hypothesis). Biotropica 2(2): 138­142.  11. FLORIDA POWER & LIGHT COMPANY. 1.987. Florida's alligators and crocodiles. Florida.  12. FUCHS, K., C. ROSS, A. POOLEY y R. WHITAKER. Artículos de piel de cocodrilo. Los cocodrilos y el hombre.  13. HALL, P. 1.985. Embryo growth curves as a method of determining the age of clutches of New Guinea crocodiles  (Crocodylus novaeguineae). Jour. Herpet. 19(4):538­541.  14. HINES, T y F. PERCIVAL. 1.987. Alligator management and value­added conservation in Florida. Valuing wildlife ­  Economic and social perspectives. Westview Press, New York.  15. IUCN. 1.986. A directory of crocodilian farming operations  16. _____. 1.989. Crocodile specialist group ­ Newsletter. Vol. 8, Jul ­ Sept.  17. KING, W. Protección y conservación. Los cocodrilos y el hombre. 18. LUGO, M. 1.995. Cría del caimán del Orinoco (Crocodylus intermedius) en la Estación Biológica Tropical Roberto Franco, Villavicencio, Meta. Rev. Acad. Colom. Cien. 19(74), Abril. 19. MAGNUSSON, W. 1.979. Distribution of caiman within the Parque Nacional da Amazonia (Tapajós). INPA.  20. MEDEM, F. 1.983. La crocodylia de Sur América. Universidad Nacional de Colombia, COLCIENCIAS. Bogotá.  21. NARANJO, H. 1.995. Metodologías para la evaluación de poblaciones silvestres de cocodrilos. Informe de avance I. Informe presentado a INDERENA, Bogotá.  22. NATIONAL RESEARCH COUNCIL. 1.993. Crocodiles as a resource for the tropics. National Academis Press, Washington.  23. NEIRA, J. 1.987. Informe sobre la reproducción del caimán negro (Melanosuchus niger SPIX, 1.828) en cautiverio.  COA.  24. ORTEGON, T. y M. QUINTERO. 1.994. Proyecto participativo de manejo para la conservación y el uso sostenible  del caimán negro. Universidad Externado de Colombia, Facultad de Finanzas y Relaciones Internacionales,  Bogotá.  25. PACHON, E. 1.982. Algunos aspectos relativos a la conservación y manejo de los Crocodylia en Colombia. INDERENA, Bogotá.  26. ROSS, C., D. BLACK y V. ONIONS. La cría de cocodrilos. Los cocodrilos y el hombre. 

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27. WEBB, G., C. MANOLIS y P. WHITEHEAD. 1.987. Wildlife management: Crocodiles and alligators. Surrey Beatty  & Sons Pty Limited. Australia. 

Caiman Population Health Monitoring in the Argentine Chaco, 2001 Recently, FVP Wildlife Health Fellow Dr. Marcela Uhart finished up a 2-year caiman health-monitoring project. Below is her report: Ranching of caiman (Caiman yacare and C. latirostris) in the Argentine Humid Chaco is being developed by the local NGO, Fundación Vida Silvestre Argentina (FVSA) at Estancia “El Cachapé”, as a wildlife sustainable use project directed towards wetland ecosystem conservation. This type of undertaking is a model strategy for environmental protection that is being promoted by FVSA. It involves a private landowner as an investor and direct beneficiary, the provincial wildlife authorities as controls, and an NGO as project supervisor and technical support provider. Enforced regulations on adult caiman harvest for the last ten years has allowed wild populations in Argentina to recuperate from extensive past over-exploitation. With quotas on the harvest of wild caiman nests and captive incubation and raising of youngsters, this ranching system intends to provide enough young to both satisfy market demands and the restocking of wild populations. Prior to project implementation, information on population parameters and habitat were obtained by FVSA biologists through aerial nest census, night counts, and satellite image analysis. Since 1998, animals raised in captivity have been reintroduced to their nest collection sites. To minimize disease risks associated with this "catch and release system", strict sanitary controls on the captive raised animals together with baseline wild population health information is necessary. In 1999, the Field Veterinary Program began a collaborative effort with FVSA to survey caiman population health. During January 2000 and February 2001, a total of 24 samples were collected from wild caiman and 46 from captive raised animals. Blood samples were collected for disease analysis and all sampled animals received a complete physical examination and were marked prior to release. All samples from 2000 have been analyzed and results presented at scientific meetings. Samples from 2001 are currently being analyzed. Tests that were run on samples from 2000 included: blood biochemistry and mineral levels, infectious disease serology including Leptospirosis and several arboviruses, and examination of fecal samples for parasite identification. Both captive and wild caimans were negative for most tests run. However, all caiman samples tested highly positive for the uncommon Leptospira interrogans strain L. Sarmin. In addition, some of the samples tested positive for two other uncommon strains of Leptospirosis, which is the first time these pathogens have been described in free-ranging caimans in Argentina. These preliminary results suggested a low but still 97

significant incidence of pathogens in both wild and captive populations; therefore sanitary conditions of artificially raised animals must continue to be strictly monitored. Additionally, other important pathogens, such as Salmonella sp. have been included in sampling efforts this year. To improve our knowledge on Leptospirosis’ role in these populations, attempts of isolation of L. Sarmin are also being conducted during this season. (For more detailed results from laboratory tests, see below.) In the following years a commercial stage of the project will begin under the direction of the local owner and the Fundación Vida Silvestre Argentina, when all environmental and legal requirements are reached. This wildlife management system might become a model for successful conservation and sustainable use of caimans and their habitat in northern Argentina. Laboratory Results: Biochemistry and mineral determinations on samples from 2000 (17 wild and 18 captive caiman) were performed by Wild Life- Lab (Dr. Maria Cristina Ferreyra Armas). Fecal samples from captive caiman were analyzed by Dr. Pablo Beldoménico at Lab. Parasitología, Fac. de Cs. Veterinarias (UNL), with negative results. Samples for infectious disease serology were submitted to several diagnostic centers. Laboratorio Azul (Drs. Alfredo Martinez and Juan Carlos Bardon) analyzed 8 Leptospira interrogans serovars, resulting negative for all individuals. Instituto Nacional de Enfermedades Virales Humanas (Dra. Gabriela Avilés) performed IHA (hemagglutination inhibition analysis) for arboviruses, including Easter Equine Enchephalitis (EEE), Western Equine Encephalitis (WEE), Venezuela Equine Encephalitis (VEE) and San Luis Encephalitis (SLE). All animals (captive and wild) were negative. Finally, Dr. Carlos Rossetti from Instituto de Patobiología (CICV, INTA Castelar) analyzed the samples for 24 L. interrogans serovars, including many uncommon strains. All caiman were strongly positive to L. Sarmin, and the highest antibody titers were found in five captive C. latirostris. Twenty-five samples also tested positive for other serovars, especially L.pyrogenes (15) and/or L.ranarum (19). This is the first report of the presence of this pathogen in free-ranging caiman in Argentina, and is only comparable to previous findings by Dr. William Karesh (FVP-WCS, pers. communication) in Belize, Brazil and Bolivia. Black Caiman

[CITIES-listed Endangered Species] Crocodilian Species - Black Caiman (Melanosucus niger): NAMES: Black caiman, Caimán, Caimán negro, Caïman noir, Lagarto negro, Jacare Açu, http://www.flmnh.ufl.edu/natsci/herpetology/CITEScroc/citesenglish/Blue8eMniger.htm Blue Page 8 - Melanosuchus niger - E: Black caiman. CITESMelanosuchus niger. Nu +2+2-44 in contact with each other. http://animaldiversity.ummz.umich.edu/site/accounts/information/Melanosuchus_niger.html ADW: Melanosuchus niger: Information: Melanosuchus niger (black caiman). ... Reproduction. Good information concerning http://animaldiversity.ummz.umich.edu/site/accounts/classification/path/Crocodylidae.html.html ADW: Crocodylidae: Classification: ...caiman). Species Caiman yacare (Jacare caiman).

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specimens. Genus Melanosuchus http://www.hipark.austin.isd.tenet.edu/projects/fourth/rainforests/wildlife/wildlife.html Wildlife: ...caiman. It measures about 4 ft. long. The largest of all the caimans is the http://nativenet.uthscsa.edu/archive/nl/9704/0123.html NATIVE-L mailing list: urgent action on French Guiana: Additionally, the Kaw wetland system contains one of the few remaining, viable, http://web.mit.edu/12.000/www/m2006/teams/taoeyang/tables.html Table(s) of Different Fauna in the Amazonian Rainforest: ...leeches, snails. Reptiles, Anaconda, black caiman, spectacled caiman, turtles, http://elib.cs.berkeley.edu/photos/fauna/com-Reptile.html CalPhotos: Browse Reptile Common Names: 1) Basilisk Lizard (2) Beaarded Dragon (1) Bearded Dragon (2) Belding Orange-throated http://www.bioweb.uncc.edu/bierregaard/tucano_journal.htm Tucano Journal: Saw a few black caiman and an iguana, but the highlight was an adult Spectacled http://itech.pjc.edu/jkaplan/zootech/Course%20Materials/herplec26.htm Crocodylians: American Alligator. Chinese Alligator. Spectacled Caiman. Black Caiman. Family http://itech.pjc.edu/jkaplan/zootech/Course%20Materials/herplec27.htm Herp Regulations & Management: Requires permit and 5 foot chain link fence. • Crocs (except dwarf), gharial, black http://www.duke.edu/~manu/home/Bibliography/CASHU.HTM Cocha Cashu Bibliography: Growth-Rates of Black Caiman Melanosuchus-Niger and Spectacled Caiman Caiman-Crocodilus, http://www.duke.edu/~djb4/Quest%20for%20the%20Blue-throated%20Macaw.htm Quest for the Blue Throated Macaw: Heinz pointed out two large Black Caiman, about 8 and 10 ft. long, that were http://darwin.bio.uci.edu/~sustain/bio65/lec05/b65lec05.htm Chapter 5: As these species became scarce, hunters turned their attention to the black caiman http://www.msu.edu/~hagersha/Templates/spectacled_caiman.htm Virtual Amazon Tour-Spectacled Caiman: ...hence the name. Young caiman are yellow and have black stripes and spots. As they http://www.nmnh.si.edu/botany/projects/cpd/sa/sa11.htm CPD: South America, Site SA11, Lowlands of Manu National Park ...: Cocha Cashu Biological Station was founded in 1969-1970, initially to facilitate http://www.nmnh.si.edu/botany/projects/cpd/sa/sa24.htm CPD: South America, Site SA24, Llanos de Mojos Region, Bolivia: ...such as rhea, capybara (Hydrochaeris hydrochaeris), "lagarto" or yacaré (Caiman http://people.uncw.edu/bruce/hon%20120/amazon%20animal%20list.htm Amazon Animal List: ...army ant. Megan Ennes (Feb 16), jaguar. leaf-cutter ant. Ian Shriner (Feb

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9), black http://hitchcock.itc.virginia.edu/Suriname/texts/proposal.html A Proposal to Fund a Process to Design a Tourism Development ...: Suriname contains some of the best sea turtle nesting beaches in the world and is http://people04.albion.edu/WBL10/dp/amazon.htm pics: A baby Black Caiman grabbed out of the water by one of our guides while spotlighting http://www.press.uchicago.edu/cgi-bin/hfs.cgi/00/14609.ctl Willink, Philip W.: A Biological Assessment of the Aquatic ...: Pantanal--essential sanctuaries for migratory birds, critical nursery grounds for http://www.cstars.ucdavis.edu/~jongreen/tbs/aquatic.html Aquatic Systems: Lago Lago at TBS. Baby black caiman. The dock. Video: click on the pictures below http://eebweb.arizona.edu/collections/herp/BiotaWeb/Species1.htm Species Records, Page 1: Melanosuchus niger (Spix, 1825) (1 Specimen). Common Name: Black Caiman. Genus http://www.webster.edu/~corbetre/haiti/history/revolution/caiman.htm Haiti: THe Bois Caiman Meeting of 1791: ...the wife of Louis Michel Pierrot, who led a black battalion at Vertieres and later http://academic.ursinus.edu/anso/anso_2003_syl_A222.htm ANTHROPOLOGY 222: Chapter 1: “Through the Emerald Door.�. Chapter 2: “The Search for http://www.bio.davidson.edu/people/midorcas/research/Field%20trips/Tortuguero2003/Tortuguero.htm Tortuguero, Costa Rica - August 2003: Crocodilians Caiman crocodylus Crocodylus acutus. ... blue heron Tricolored heron Little http://www.fiu.edu/~acaten01/references/bibcc.html Scientific publications from Cocha Cashu, Manu NP (Peru): Growth rates of black caiman (Melanosuchus niger) and spectacled caiman (Caiman http://utweb.ut.edu/faculty/mmeers/bcb/dh.html The Bibliography of Crocodilian Biology: DH: Dangerous to man? A record of an attack by a black caiman (Melanosuchus niger) in http://utweb.ut.edu/faculty/mmeers/bcb/sz.html The Bibliography of Crocodilian Biology: SZ: J. Sci. 20: 13-18. Vasquez, PG 1991. Melanosuchus Gray black caiman. Catalogue of http://plaza.ufl.edu/wlme/peru/splist.htm species list: 1 April 2002- Manu River, Manu Reserve Zone. White Caiman-Caiman crocodilus. http://plaza.ufl.edu/wlme/peru/rainforest.htm Rainforest: Squirrel Monkey-Saimiri sciureus. Amazon Horned Frog-Ceratophrys cornuta. Black http://www.library.wwu.edu/ref/subjguides/ed/edtopics/win02black.htm

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Education Topic - Celebrating Black History: Maman-Caiman = Mother Crocodile. [English]. Birago Diop. Trans. Rosa Guy. Illustrated http://www.american.edu/projects/mandala/TED/reptile.htm REPTILE Case: Illegal, black market trading continues all over the world in ivory, elephant feet http://www.uwsp.edu/geo/faculty/heywood/geog358/exotics/exoticRL.htm COMMON NAME: ...reptile; lizard black iguana, Ctenosaura spp. South America, USA, ... reptile; lizard http://www.southampton.liu.edu/news/travel/tropicalfieldstudies/reflections.html Travel Programs: The initial rush hit me when I pictured a black caiman slipping down the mud into http://bio.bd.psu.edu/biobd497g/CostaRicaTrip0203/reptiles.htm Reptiles: Spectacled Caiman, Caiman crocodilus. Glass Frog, Centrolenella hyalinoatrachium. http://wildlife.tamu.edu/publications.cfm?catID=17 wildlife.tamu.edu - Extension Wildlife and Fisheries Sciences ...: Caimans (Caiman spp.), imported from Central and South America, are occasionally http://www.lib.lsu.edu/lib/lis/awards/cskalph.html

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Higher Taxa

Crocodylidae (Alligatoridae) Crocodylia, crocodiles (alligators

Subspecies Common Name

E: Dwarf caiman, Cuvier's smooth-fronted caiman Local names: Jacaré pagua, Cachirre, Cocodrilo, Musky caiman. G: Brauen-Glattstirnkaimans

Synonym

Crocodilus palpebrosus CUVIER 1807: 35 Jacaretinga moschifer SPIX 1825 (fide DUMÉRIL & BIBRON 1836: 69) Champsa gibbiceps NATTERER 1840: 324 Champsa palpebrosa — WAGLER 1830: 140 Alligator palpebrosus — DUMÉRIL & BIBRON 1836: 67 Paleosuchus palpebrosus — KING & BURKE 1989 Paleosuchus palpebrosus — GORZULA & SEÑARIS 1999 106

Location

Bolivia, Brazil (Goias etc.), Colombia, Ecuador, French Guiana, Guyana, NE Paraguay, Peru, Surinam, Venezuela. Terra typica: "Cayenne," French Guiana

Holotype

Holotype: MNHN 7530, according to Vaillant 1898, and MNHN 7531 according to Vaillant 1898

Comment

Slightly larger distribution than that of the sympatric Paleosuchus trigonatus, extending into Paraguay and further into Brazil

References

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Barban Zucoloto, Rodrigo; Priscilla Marqui Schimidt Villela; Luciano Martins Verdade and Luiz Lehmann Coutinho 2006. Cross-species microsatellite amplification in South American Caimans (Caiman spp and Paleosuchus palpebrosus). Genetics and Molecular Biology 29 (1): 7578 Campos, Zilca and Tãnia M. Sanaiotti. 2006. Paleosuchus palpebrosus Nesting. Herpetological Review 37 (1): 81 Cuvier, G. 1807. Sur les différentes especes de crocodiles vivans et sur leurs caracteres distinctifs. Ann. Natl. Mus. Hist. Nat. Paris 10: 8-86. • Duméril, A.M. C. and G. Bibron. 1836. Erpetologie Générale ou Histoire Naturelle Complete des Reptiles. Vol.3. Libr. Encyclopédique Roret, Paris, 528 pp. Gorzula Stefan & Senaris J. Celsa 1999. In: Contribution to the herpetofauna of the Venezuelan Guayana. I: a data base. Scientia Guaianae, Caracas, No. 8 [1998], 269+ pp.; ISBN 980-6020-48-0 Hoogmoed M.S.; de Avila-Pires T C S 1991. Annotoated checklist of the herpetofauna of Petit Saut, Sinnamary River, French Guiana. Zoologische Mededelingen 65: 5388 • Magnusson W E 1992. Paleosuchus palpebrosus. Catalogue of American Amphibians and Reptiles 554 1992: 1-2 • Magnusson W E 1992. Paleosuchus. Catalogue of American Amphibians and Reptiles 553 1992: 1-4 • Medem, F. 1953. Contribuciones a la taxonomía y

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distribución del yacaré negro, Paleosuchus palpebrosus (Cuvier) en Colombia Rev. Colomb. Antropologia 1 (1): 409-419 • Medem, F. 1967. El genero Paleosuchus en Amazonia Atas do Simp.sobre Biota Amaz. 3: 141-162 • Medem, F. 1972. El primer nacimiento de Paleosuchus palpebrosus (Crocodylia, Alligatoridae) Rev. Acad. Colomb. Ci., Ex., Fis., Nat. 53: 33-36 • Natterer 1840. Ann. naturhist. Hof. Mus. Wien 2: 322, 324 • Nickel, H. & Auliya, M. 2004. Krokodile - faszinierende Überlebenskünstler. Draco 5 (20): 4-19 • Roos, Jonas; Ramesh K. Aggarwal, Axel Janke 2007. Extended mitogenomic phylogenetic analyses yield new insight into crocodylian evolution and their survival of the Cretaceous–Tertiary boundary. Molecular Phylogenetics and Evolution 45: 663–673 • Scott, N.J.;Aquino, A.L.;Fitzgerald, L.A. 1990. Distribution, habitats, and conservation of the caimans (Alligatoridae) of Paraguay Vida Silv. Neotrop. 2 (2): 4351 • Spix, J. B. von 1825. Animalia nova sive species nova lacertarum quas in itinere per Brasiliam annis MDCCCXVII-MDCCCXX jussu et auspicius Maximiliani Josephi I Bavariae Regis suscepto collegit et descripsit Dr. J. B. de Spix. Lipsiae: T. O. Weigel; F. S. Hübschmanni, Monachii, 26 pp. • Thireau, Michel;Sprackland, Robert George;Sprackland, Teri 1998. A report on Seba's specimens in the herpetological collection of the Muséum National d'Histoire Naturelle, Paris, and their status as Linnaean types The Linnean 13 (4): 38-45 • Trutnau, L. & Sommerlad, R. 2006. Crocodilians. Their natural history and captive husbandry. Edition Chimaira, Frankfurt, 646 pp. [review in Reptilia GB 48: 8-10] • Trutnau, L. & Sommerlad, R. 2006. Krokodile - Biologie und Haltung. Edition Chimaira, Frankfurt, 646 pp. [review in Reptilia Münster 11 (6): 95-96] • Vaillant, M.L. 1898. Contribution à l'Etude des 108

émydosaurians. Catalogue raisonné des jacaretinga et alligator de la collection du museum. Nouv. Arch. Mus. Hist. Nat. Paris (3) 10: 143-212 • Vaz-Silva, W. et al. 2007. Herpetofauna, Espora Hydroelectric Power Plant, state of Goia?s, Brazil. Check List 3(4): 338-345 Wermuth,H. & Fuchs,K. 1978. Bestimmen von Krokodilen und ihrer Häute. Gustav Fischer Verlag, Stuttgart - New York, 100 pages, [ISBN 3-437-30268-X] • Ziegler, T. & Olbort, S. 2004. Genitalstrukturen und Geschlechtsunterscheidung bei Krokodilen. Draco 5 (20): 39-47

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Ziegler, T.; Behrmann, H.-J.; Beek, B. & Rütz, N. 2004. Erste Naturbruten des Brauen-Glattstirnkaimans (Paleosuchus palpebrosus) im Aquarium des Kölner Zoos Draco 5 (20): 28-31

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Historical Herp Literature available from The Reptile Database: • • •

Linnaeus - Systema Naturae, Herpetological part, pages 194-229 [2.8 MB] Proceedings of the Academy of Natural Sciences of Philadelphia 1841-1899 Duméril & Bibron (1854): descriptions of new snakes

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Annals and Magazine of Natural History (1838-1899, all reptile papers) (CDROM 6-12/2002) Proceedings of the Academy of Natural Sciences of Philadelphia 18411899, all reptile papers (CD-ROM 3/2001) Zoologischer Anzeiger, 1880-1905, all 127 reptile papers (CD-ROM 2008). Duméril & Bibron (1854): Érpetologie Génerale, Vol. 1 - General Herpetology, 450 pp. (CD-ROM 3/2005) Duméril & Bibron (1835): Érpetologie Génerale, Vol. 2 - Turtles, 680 pp. (CD-ROM 6/2003). Duméril & Bibron (1836): Érpetologie Génerale, Vol. 3 - Geckos, monitors, chameleons, crocodiles, 528 pp. (CD-ROM 7/2004) Duméril & Bibron (1839): Érpetologie Génerale, Vol. 4 - Agamas and iguanas, 571 pp., as PDF (CD-ROM 9/2006) Duméril & Bibron (1839): Érpetologie Génerale, Vol. 5 - Skinks, wall lizards, etc. 860 pp. (CD-ROM 3/2006) Duméril & Bibron (1844): Érpetologie Génerale, Vol. 6 - Boas, pythons, and blind snakes (CD-ROM 12/2003) Duméril & Bibron (1854): Érpetologie Génerale, Vol. 7 - Snakes, 1536 pp. (2 vols., see samples; CD-ROM 12/2002). Duméril & Bibron (1854): Érpetologie Génerale, Vol. 8 - Amphibians (to be released as an addendum in 2008). Duméril & Bibron (1854): Érpetologie Génerale, Vol. 9 - Turtles 2, iguanas 2, to be released in 2008. Order CDs online by credit card via Kagi.com (secure web site)

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Girard, S.F. (1858) United States Exploring Expedition..., C. Sherman & Son, Philadelphia, xv, 492 pp. Günther, A.C.L.G. (1885-1902) Reptilia and Batrachia. Biologia CentraliAméricana. Taylor, & Francis, London, 326 pp

Publications from and on the database: Uetz, P. (1996) Herpetologie im Internet. Elaphe 4 (3): 60-64 Uetz,P. & Etzold,T. (1996) Die EMBL-Reptiliendatenbank. Elaphe 4/96: 49-53 Uetz,P. & Etzold,T. (1996) The EMBL/EBI Reptile Database. Herpetological Review 27 (4): 174-175 Uetz,P. (2000) How many reptiles species? Herpetological Review 31 (1): 13-15 Hallermann,J., Dirksen,L. & Uetz,P. (1999) Liste der Neubeschreibungen von Reptilien des Jahres 1998, mit Nachträgen der Jahre 1996 und 1997. Elaphe 7 (1): I-VII Hallermann,J., Schmitz,A.. Dirksen,L. & Uetz,P. (2000) Liste der Neubeschreibungen von Reptilien des Jahres 1999, mit Nachträgen der Jahre 1998 und 1997. Elaphe 8 (2): 53-61 Hallermann,J., Schmitz,A.. Dirksen,L. & Uetz,P. (2001) Liste der Neubeschreibungen von Reptilien des Jahres 2000, mit Nachträgen des Jahres 1999. Elaphe 9 (2): 40-45

The papers by Hallermann et al. provide annual lists of newly described species. All those species are also included in the EMBL Reptile Database (of course!). A cumulation of these and other species described in the 1990ies is available (see below). Uetz,P. & Schmitz,A. (2001) Fast 1000 in 10 Jahren - ein Nachtrag zum Thema "Neue Reptilientaxa" [pdf]. Elaphe 9 (4): 51-53

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This paper gives an update on a preceding paper by Schmitz et al. that listed (almost) all species that have been described from 1990 to 1999. The updated list is available as pdf file. Uetz,P. (2002) Alte Bücher - neue Technik: Das Projekt "Historische Literatur" bei der EMBL-Reptiliendatenbank. Beiträge zur Literatur und Geschichte der Herpetologie und Terrarienkunde, Bd. II: 41-46 Hallermann,J. & Uetz,P. (2002) Liste der Neubeschreibungen von Reptilien des Jahres 2001, mit Nachträgen des Jahres 2000. Elaphe 10 (2): 90-96 Hallermann,J. & Uetz,P. (2004) Liste der Neubeschreibungen von Reptilien des Jahres 2002, mit Nachträgen des Jahres 2001. Elaphe 12 (2): 85-90 Hallermann,J. & Uetz,P. (2005) Liste der Neubeschreibungen von Reptilien des Jahres 2003. Elaphe 13 (2): 69-74 Uetz, P.; Goll, J. & Hallermann, J. (2007) Die TIGR-Reptiliendatenbank. Elaphe 15 (3): 16-19

Reptile Systematics:

• • • • • •

Terrestrial Vertebrates (Tree of Life) Zoological Record: Resource Guide - Reptilia Reptile sequences in the GenBank DNA Database CROCODILIAN, TUATARA, AND TURTLE SPECIES OF THE WORLD (by F. W. King and R. L. Burke, eds.) Turtles of the World (Iverson et al.) Turtles of the World (Ernst, Altenburg & Barbour)

Herpetological Directories:

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Reptiles (Yahoo) Combined Index to Herpetological Collections

Herpetological Bibliographies:

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Biodiversity Heritage Library Member Projects: Girard, S.F. (1858) United States Exploring Expedition..., C. Sherman & Son, Philadelphia, xv, 492 pp. 112

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Günther, A.C.L.G. (1885-1902) Reptilia and Batrachia. Biologia CentraliAméricana. Taylor, & Francis, London, 326 pp

Historical Litearture:

• • •

Current contents of herpetological journals HERPFAUN (faunistic bibliography by Charles H. Smith) Historical Documents of the Virginia Herpetological Society

Other Vertebrate databases or checklists:

• • • • •

Amphibians: Frost's Amphibian Species of the World; Amphibiaweb; Globalamphibians.org Birds: Avibase, The Sibley/Monroe World List of Bird Names Fish: CAS Fish Database , Fishbase Mammals: Mammal Species of the World Introduced reptiles to North America: CNAH

Systematic Zoology (General):

• • • • • • • •

The Tree of Life Home Page Zoology Resource Guide (BIOSIS Index) Index to Organism Names (TRITON/BIOSIS) SPECIES 2000 HOME PAGE IUCN Red List of Threatened Animals Interagency Taxonomic Information System (ITIS) International Code of Zoological Nomenclature Phylogenetics Databases and Information

Other sites:

• • •

Reptile Chromosome database Snake Scalation at Wikipedia Herpfaun (herpetofaunistic bibliography by C.H. Smith)

Melanosuchus niger - Jacaré-açu, Jacaré-gigante

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Taxonomia: Filo: Cordado Sub-filo: Vertebrado Super-Classe: Tetrápodo Classe: Reptilia Sub-Classe: Diapsida Infra-Classe: Archosauria Ordem: Crocodylia Sub-Ordem: Eusuchia Família: Alligatoridae Gênero: Melanosuchus Espécie: Melanosuchus niger (Spix, 1825)

Nome Científico: Melanosuchus niger (Spix 1825). Melanosuchus significa "crocodilo negro", derivado de melas (genitivo grego para “negro”) + soukhos (grego para "crocodilo", precedente para o latim suchus); niger significa "negro" (latim), referindo a coloração muito escura dessa espécie.

Nomes Comuns: Jacaré-açu, Jacaré-negro, Jacaré-gigante, “Black caiman”, “Caimán”, “Caimán negro”, “Caïman noir”, Lagarto-negro, Jacaré-Assú, Jacare-Uassu, Jacaré Una, “Yacare Assu”.

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Características: É a maior espécie da família Alligatoridae (os machos podem alcançar pelo menos 4 m de comprimento, chegando a extremos de até 6m). Sua aparência é semelhante à do Alligator mississippiensis. Como o próprio nome comum sugere, tem uma coloração escura. A mandíbula tem faixas acinzentadas nos jovens e marrons nos mais velhos. Juvenis possuem faixas amareladas ou brancas na lateral do corpo, que vão desbotando gradualmente com a maturidade do animal. Tem olhos grandes, nariz relativamente estreito e uma crista ossificada que se estende dos olhos até o nariz, como em outros jacarés.

Status: Recentemente o jacaré-açu foi excluído da Nova Lista Nacional das Espécies da Fauna Brasileira Ameaçadas de Extinção. Por

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Bibliografia sobre Crocodilianos

AZEVEDO, J.C.N. Crocodilianos: Biologia, Manejo E Conservação. JOÃO PESSOA: ARPOADOR, 2003. 122 P. CAMPOS, Z. Efeito do habitat na fecundidade das fêmeas, sobrevivência e razão social dos jovens dos jacarés do Pantanal. Corumbá: Embrapa Pantanal, 2003, 22 p. (Boletim de Pesquisa e Desenvolvimento, 42). CAMPOS, Z. Observações sobre a biologia reprodutiva de 3 espécies de jacarés na Amazônia Central. Corumbá: Embrapa Pantanal, 2003, 17 p. (Boletim de Pesquisa e Desenvolvimento, 43). CAMPOS, Z., COUTINHO, M.E., ABERCROMBIE, C. Ecologia e estado de conservação do jacaré-paguá na serra do Amolar, Pantanal sul. In: Simpósio sobre recursos naturais e sócio-econômicos do Pantanal, 4. 2004, Corumbá, Anais. Corumbá, 2004. DA SILVEIRA, R. Conservação e manejo do jacaré-açu (Melanosuchus niger) na Amazônia. In: VERDADE, L.M. e LARRIERA, A. [Eds]. Conservação e manejo de jacarés e crocodilos da América Latina, v. 2. Piracicaba: C.N. Editora, 2002. p. 61-78. DA SILVEIRA, R., MAGNUSSON, W.E., CAMPOS, Z. Monitoring the distribution, abundance, and breeding areas of Caiman crocodilus crocodilus and Melanosuchus niger in the Anavilhanas Archipelago, Central Amazonia, Brazil. Journal of Herpetology, v. 31, n. 4, p. 514-520, 1997. FARIA, I.P., DA SILVEIRA, R., THOISY, B., MONJELÓ, L.A., THORBJARNARSON, J., HRBEK, T. Genetic diversity and population structure of Amazonian crocodilians. Animal Conservation, v. 7, p. 265-272, 2004. MAGNUSSON, W.E., SILVA, E.V.DA, LIMA, A.P. Diets Of Amazonian Crocodilians. JOURNAL OF HERPETOLOGY, V. 21, N. 2, P. 85-95, 1987. MARQUES, E.J., MONTEIRO, E.L. Ranching de Caiman crocodilus yacare no Pantanal de Mato Grosso do Sul. In: VERDADE, L.M. e LARRIERA, A. [Eds]. La conservación y el manejo de caimanes y crocodilus de América Latina, v. 1. Santa Fé: Fundación Banco Bica, 1995. p.189-211. (232 p.) SANTOS, S.A. Drieta E Nutrição De Crocodilianos. CORUMBÁ: EMBRAPA-CPAP, 1997. 59 P. SARKIS-GONÇALVES, F., BOSCOLO, F.N., CASTRO, A.M.V., VERDADE, L.M. Influencia da dieta na formação de osteodermos em filhotes de jacarés-de-papo-amrelo (Caiman latirostris) em cativeiro. In: VERDADE, L.M., LARRIERA, A. [Eds]. Conservação e manejo de jacarés e crocodilos da América Latina, v. 2. Piracicaba: C.N. Editora, 2002. p.157-165. THORBJARNARSON, J.B. Diet of the spectacled caiman (Caiman crocodilus) in the Central Venezuelan Lhanos. Herpetológica, v.49, n.1, p.108-117, 1993. VERDADE, L.M. A exploração da fauna silvestre no Brasil: jacarés, sistemas e recursos humanos. Biota Neutropica, v. 4, n. 2, p. 1-12, 2004. VERDADE, L.M. Biologia reprodutiva do jacaré-do-papo-amarelo (Caiman latirostris) em São Paulo, Brasil. In: VERDADE, L.M. e LARRIERA, A. [Eds]. La conservación y el manejo de caimanes y crocodilus de América Latina, v. 1. Santa Fé: Fincación Banco Buca, 1995. p.57-79. (232 p.) VERDADE, L.M., SANTIAGO, M.E.B. [Eds.] Jacaré do papo amarelo – Caiman latirostris. In: Workshop sobre conservação e manejo do jacaré-do-papo-amarelo (Caiman latirostris), I. Anais... Piracicaba: CIZBAS/ESALQ, 1990. ZUCOLOTO, R.B. Desenvolvimento de seqüências de DNA microsatélite para estudo de populações remanescentes de Jacaré-de-papo-amarelo (Caiman latirostris), da região central do Estado de São Paulo. Piracicaba, 2003. 118p. Tese (Doutorado). Escola Superior de Agricultura Luiz de Queiroz, Universidade de São Paulo.

Id: 365948 Autor: Cabrera Peña, Jorge; Protti Quesada, Maurizio; Urriola Hernández, Mario; Cubero Murillo, Rolando. Título: Distribución y abundancia de Caiman crocodilus en el Refugio Nacional de Vida

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Silvestre Caño Negro, Costa Rica / Distribution and abundance of Caiman crocodilus in the Caño Negro National Wild Life Refuge, Costa Rica Fonte: Rev. biol. trop;51(2):571-578, jun. 2003. tab, maps, gra. Idioma: Es. Resumo: The distribution and abundance of a population of Caiman crocodilus fuscus were estimated by monthly counting of eye-shines at night, from February 1999 to March 2000 in six transects of Río Frío in the Caño Negro National Refuge (RNVSCN), Northern Costa Rica. March was the month with the greatest abundance of caimans observed. The visible fraction of the population (PV2 index) fluctuated between 42.59% to 54.71% during the wet season and 35.49% to 53.93% in the dry season. The transects of river with greater abundance of caimans were Terrón-Sabogal and Sabogal-Playuela. Significant differences were determined in the abundance of caimans between transects, except the transects Entrada San Sebastían-Las Cubas and Las Cubas-Entrada Caño Los Patos and Entrada Caño Los Patos-Terrón and Boca Sabogal-Playuela. The population of estimated brown caiman in this study was 2283.48 +/- 313.5. The statistical analysis by seasons did not show significant differences in the number of caimans observed. Estimated mean number of caimans per km of river was 74.36/km for 30.7 km of habitat. The results of this study indicated that the fluctuation in population density during the seasons is attributable to local movements. (AU) Descritores: Jacarés e Crocodilos/classificação -Dinâmica Populacional Densidade Demográfica Estações do Ano Costa Rica Limites: Animais Responsável: BR1.1 - BIREME

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Variaciones fisiológicas de electrolitos séricos (Na, K, Ca, P, 3 Mg, Cu) en Caiman latirostris y Caiman yacare 6 (Crocodylia: Alligatoridae) alojados en criaderos - J.A.

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PD Investigac F ión

Edad, sexo, estación del año y sistema de manejo 3 modifican los parámetros leucocitarios durante el 7 cautiverio de Caiman latirostris y Caiman yacare (Crocodylia: Alligatoridae) - Mussart, N. B., Barboza N. N., Fioranelli

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Coppo, N.B. Mussart, N.N. Barboza, S.A. Fioranelli, G.A. Koza y W.S. Prado

S. A., Koza, G. A., Prado, W. S. y Coppo, J. A. (en inglés)

3 8

Carnes no tradicionales

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Cambios del eritrograma durante el cautiverio de Caiman latirostris y Caiman yacare - Barboza, N. N., Mussart, N. B., Prado,

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Ledesma, M. A. y Gunski, R. J.

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Criadero modelo de yacarés en Corrientes, un proyecto de caimanes de Formosa y yacarés santafesinos - El

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Evaluación clínica de reptiles

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J. Urbieta

Comercial

R. y Caffer M. - N. Varela

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Singing to the Plants Shamanism and the Medicine Path

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Steve Beyer has doctorates in religious studies and in psychology. He has been a university professor, lawyer, wilderness guide, and peacemaker. He has studied both wilderness survival and the indigenous cultures of North and South America. He has studied sacred plant medicine with traditional herbalists in North America and with ayahuasqueros in the Upper Amazon, where he received coronación by banco ayahuasquero don Roberto Acho Jurama. He has worked with ayahuasca and other sacred plants in the Amazon, peyote in ceremonies of the Native American Church, and huachuma in Peruvian mesa rituals. He has served as an editor of the Journal of Shamanic Practice and is a contributing editor of Ayahuasca.com. His book on shamanism, sorcery, and plant medicine in the Upper Amazon, Singing to the Plants: A Guide to Mestizo Shamanism in the Upper Amazon, is to be published this fall by the University of New Mexico Press. View my complete profile

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121

Wednesday Male Potency Enhancers

In the Amazon, products purporting to enhance male sexual potency are sold in stalls and shops all over the jungle. These drinks are probably as well known for their names as for their ingredients — Rompecalzón, Rip-Your-Shorts; Levántate Lázaro, Arise Lazarus!; Para Para, Stand up! Stand up!; Tumba Hembra, Knock Her Over; Siete Veces Sin Sacar, Seven Times Without Pulling Out; Levántate Pájaro Muerto, Arise Dead Bird! These aphrodisiacs are made from both plants and animal parts, the latter primarily the ullo, penis, of various animals — the achuni, coatimundi (Nasua nasua), a relative of the raccoon, which is believed to have a penis that is always erect; the machín, capuchin monkey (Cebus spp.); and the lagarto negro, black caiman (Melanosuchus niger). It is popularly said that ingesting achuni ullo induces a priapism so profound as to survive death, requiring that a hole be cut in the coffin to accommodate it.

Two plants in particular are thought to have male potency enhancement effects — chuchuhuasi (Maytenus macrocarpa), shown at right, with the cut bark above at left; and clavohuasca, clove vine (Tynanthus panurensis). Clavohuasca is reputed to work as a libido enhancer for women as well. Interestingly, both of these — along with a number of the plants with which they are mixed — are considered hot plants, used to treat cold conditions, such as arthritis and rheumatism; in addition, the bark with which they are mixed comes from trees that produce strong durable hardwood used in construction for posts, supports, and uprights — a good example of the doctrine of signatures. The most frequently used hardwoods for this purpose are cocobolo (Schinopsis peruviana), cumaseba (Swartzia polyphylla), huacapú, ironwood (Minquartia guianensis), icoja (Unonopsis spp.), and tahuari (Tabebuia spp.).

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Herbs and bark are then dissolved in aguardiente. Aguardiente is, literally, agua ardiente, burning water. It is distilled from the fermented first squeezing of sugar cane, unlike rum, which is made from molasses, a byproduct from the processing of the sugar cane into sugar. The same drink is called cachaça in Brazil. In Colombia, aguardiente is sometimes flavored with anise. But in the Peruvian Amazon, aguardiente is straightforward, unflavored, potent, sold in recycled bottles or by the shot in tin-roofed bars and thatched bodegas throughout the jungle. Some recipes are relatively straightforward: the chuchuhuasi drink is a maceration in aguardiente of chuchuhuasi bark; abejachado is the chuchuhuasi drink with honey added; achuni ullo, coatimundi penis, is a maceration in aguardiente of scrapings from the dried penis of a coatimundi. More complex recipes can add to chuchuhuasi both hot plants, such as abuta (Abuta grandifolia) and ipururo (Alchornea castaneifolia), and the bark of such hardwood construction trees as huacapú and cumaseba, mixed with honey. The various Rompecalzón recipes use, in similar fashion, clavohuasca bark instead of chuchuhausi. I am sorry to report that empirical studies of efficacy are lacking. General tonics such as Siete Raíces, Seven Roots, and Veintiun Raíces, Twenty-One Roots, often contain chuchuhuasi or clavohuasca or both, and thus claim potency enhancement along with numerous other benefits.

The term raíces is metaphorical, since most of the

ingredients are tree bark rather than roots.

The ingredients can vary from place to place; I have collected four different recipes of Siete Raíces, all of which contain chuchuhuasi and three of which contain clavohuasca. These drinks are basically aguardiente flavored with bark and herbs, and make a very pleasant apéritif, apart from their claimed uplift. The capinurí palm (Maquira coriacea) is also worth mentioning. The ends of its fallen branches — pictured on the left — look remarkably like erect penises, and wearing a two- or three-inch piece of the branch end on a string around the neck is considered to increase virility — another example of the doctrine of signatures. The phallic ends of the branches are also the subject of a great deal of ribald humor.

Black caiman (Melanosuchus niger) • • • • •

Facts & Status Description Range & Habitat Biology Threats & Conservation 123

• •

Further information Glossary & References

Facts Previously known as:

Caiman niger

Kingdom

Animalia

Phylum

Chordata

Class

Reptilia

Order

Crocodylia

Family

Alligatoridae

Genus Size

Melanosuchus (1) Length: at least 4 m (2)

Status Classified as Lower Risk / Conservation Dependent (LR/cd) on the IUCN Red List 2007 (1) and listed under Appendices I and II of CITES (3).

Description This impressive aquatic hunter is the largest of all alligator species, with reports of individuals measuring six metres (2). The black caiman superficially resembles the American alligator (4), and as its name suggests, its protective armoured skin is dark in colour. Pale yellow or white bands of dots pattern the sides of the body, while the lighter grey head has dark bands across the jaws (4). As the caiman matures, this banding gradually fades (2). The snout is fairly wide at the base but becomes rather narrow and pointed and (4), like 124

other caiman, a bony ridge extends from above the large eyes, down the snout (2).

Range The black caiman occurs mainly in the Amazon Basin, although its range does also extend further north (4). It occurs in Bolivia, Brazil, Colombia, Ecuador, Guyana, Peru, Venezuela (2), and in French Guiana, where the largest populations remain (4). View a distribution map for this species at UNEP World Conservation Monitoring Centre.

Habitat This aquatic reptile occurs in shallow, freshwater habitats such as slowmoving rivers, streams and lakes, and ventures into flooded savannah and wetlands (2) (4).

Biology Black caiman typically hunt at night, using their acute sight and hearing to locate their prey (2). Fish comprise the major part of the black caiman's diet, particularly catfish and the much-feared piranha, but adult black caiman also tackle much larger prey such as capybara, turtles and deer (4). Domestic animals such as dogs and pigs may be taken by large adult caiman, and there are even reports of people being the victim of an attack. Juvenile black caiman stick to smaller foods, including crustaceans, other invertebrates such as snails, and fish (4). Female black caiman are thought to start nesting during the dry season when water levels fall and fish are forced to congregate in shallow pools, providing an easy and plentiful meal (4). Plant material is used to build a mound nest measuring about 1.5 metres across, into which a large clutch of up to 65 eggs are laid (4). The female will remain close to the nest, waiting for between 42 and 90 days until the eggs begin to hatch, before opening the nest to assist with the hatching process (2). As many females often nest within close proximity, large numbers of hatchlings all emerge at once at the beginning of the wet season, gaining some safety in numbers (2).

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Threats For many years, the black caiman was heavily hunted for its tough skin which produces shiny, black leather (2). Intensive hunting began in the 1940s, and continued into the 1970s and beyond (2) (4), with around an incredible 66,000 hides being exported from Colombia each year in the early 1970s (4). As a result of this extreme hunting pressure, the overall population of black caiman declined by 99 per cent over the last century and it is now virtually extinct in some locations, such as Colombia and the Amazon River itself (4). Illegal hunting continues to impact the black caiman, in addition to the destruction of its habitat, through deforestation and the burning of swamplands (2). Competition with the more numerous spectacled caiman (Caiman crocodilus) may also inhibit the recovery of black caiman populations (2). The impact of reduced black caiman numbers can be felt in some areas, such as Brazil and Bolivia, where capybara populations, free from this voracious predator, have increased, causing a rise in crop damage. Similarly, an increase in piranha numbers in flooded pastures has resulted in an increase in attacks on cattle (4).

Conservation Except for certain populations in Brazil and Ecuador, the black caiman is listed on Appendix I of the Convention on International Trade in Endangered Species (CITES), meaning that international trade in this species is only permitted in exceptional circumstances. Those other populations are listed on Appendix II of CITES, meaning that annual quotas are set and the trade is carefully monitored (3). In nearly all the countries in which the black caiman is found, the species is protected or is included in laws prohibiting commercial hunting. However, these laws can be difficult to enforce and illegal hunting remains a significant problem (5), compounded by the fact that black caiman skins can be difficult to differentiate from the more common spectacled caiman (2) (5). In 1990, a captive breeding and reintroduction programme was initiated in Bolivia (5). As well as enforcing existing laws, captive breeding and reintroduction programmes need to be implemented in other countries to assist the recovery of this remarkable reptile (2).

Further Information For further information on the black caiman see: 126

•

Crocodilian Species www.flmnh.ufl.edu/cnhc/csp_mnig.htm

List:

Authentication This information is awaiting authentication by a species expert, and will be updated as soon as possible. If you are able to help please contact: [email protected]

Glossary Crustaceans: Diverse group of arthropods (a phylum of animals with jointed limbs and a hard chitinous exoskeleton) characterised by the possession of two pairs of antennae, one pair of mandibles (parts of the mouthparts used for handling and processing food) and two pairs of maxillae (appendages used in eating, which are located behind the mandibles). Includes crabs, lobsters, shrimps, slaters, woodlice and barnacles. Invertebrates: Animals with no backbone.

References 1. IUCN

Red http://www.iucnredlist.org

List

(June,

2007)

2. Crocodilian

Species List (May, http://www.flmnh.ufl.edu/cnhc/csp_mnig.htm

3. CITES

(June,

2008)

2007)

http://www.cites.org 4. Alderton, D. (2004) Crocodiles and Alligators of the World. Facts on

File, Inc, New York. 5. Ross, J.P. (1998) Crocodiles: Status Survey and Conservation Action

Plan. IUCN, Gland, Switzerland and Cambridge, UK.

An analysis of the effect of hunting on Caiman crocodilus and Melanosuchus niger based on the sizes of confiscated skins

127

George Henrique Rebêlo* and William E. Magnusson Instituto Nacional de Pesquisas da Amazônia, C.P. 478, 69.000, Manaus, AM, Brazil

Available online 26 June 2003.

Abstract The size distributions of skins of Caiman crocodilus and Melanosuchus niger confiscated by the Instituto Brasileiro de Desenvolvimento Florestal in the regions of Manaus and the Rio Trombetas were compared with the size distributions of wild populations. The comparison indicates that hunting is selective, with 110 cm and 100 cm being the approximated lower limits for C. crocodilus and M. niger respectively. The size difference between animals entering the hunted population and those entering the breeding population combined with presumed growth rates of the two species indicate that there could be some recruitment to the breeding population of C. crocodilus one year after intensive hunting but that M. niger would require approximately three years.

Article Outline • References *

Present address: Instituto Brasileiro de Desenvolvimento Florestal, Brasilia.

Crocodilian Biology Database EVOLUTION | MORPHOLOGY | BIOLOGY | BEHAVIOUR | CONSERVATION | LORE | FAQ

INDEX:

EVOLU TIO N & TAXO NOMY

128

Introduction C. crocodilus C. latirostris C. yacare Subspecies M. niger Paleosuchus Conclusion References Glossary

EVOLUTION

MORPHOLOGY

GENERAL BIOLOGY

BEHAVIOUR

CONSERVATION

LORE

FREQUENTLY ASKED QUESTIONS

129

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130

to warrant placing it in another genus. It is

interesting that

Schmidt refrained from doing so because it would ignore the uniqueness of the broadsnouted caiman, which he also retained in Spix's Caiman; recent analyses by Poe (1996) indicate that these two taxa may be sisters, and implies that Melanosuchus should be returned to the genus Caiman.

Paleosuchus: The dwarf or smooth-fronted caimans were reviewed by Medem (1958). The specific epithets of the caimans, palpebrosus and trigonatus, follow the first descriptions by Cuvier and Schneider, respectively. Both were originally described as members of the nowdefunct genus Crocodilus. Paleosuchus was first proposed by Gray (1862) as a subgenus of Caiman and included only Schneider's trigonatus. Müller (1924) pointed out that Laurenti's (1768) figure of Crocodylus niloticus (the Nile crocodile) is in fact a smooth-fronted caiman, specifically Schneider's smoothfronted caiman (cf., P. trigonatus). This revealed a problem. Later, Mller published a revision, assigning C. niloticus to the taxon formerly known as Caiman trigonatus (subgenus Paleosuchus) Gray and thereby, as noted by Schmidt (1928), wreaking havoc on crocodilian nomenclature. While Müller was certainly justified under the auspices of the Code in making the name change, Schmidt (1928) correctly (in my opinion) argued that to follow Müller would result in such chaos that the ICZN should invoke its plenary powers (as per Article 79) to rectify the situation. In the interim, Schmidt opted to follow Gray (1862), except that he considered the smooth-fronted caimans "generically-distinct," and for this reason, used Paleosuchus as their generic name. It is worth noting that Schmidt was the first worker to use the combination of generic and specific epithets in common use today. In his review, Medem agreed that Müller's recommendations would be disastrous and "should under no circumstances be followed (1958: 228)."

CONCLUSION: In conclusion, therefore, what can we say about caiman taxonomy? I have illustrated some of the circuitous routes we have taken to arrive at our present caiman nomenclature. According to a recent analysis by Poe (1996), the generic distinctness of Melanosuchus may be questionable. The black and broad-snouted caimans were found to be sister taxa in a combined analysis of available phylogenetic data on caiman relationships. The black caiman was Spix's "other Caiman," Caiman niger. This name has priority over Werner's Melanosuchus, and, as Poe suggested, should be applied to this taxon. Beyond this change, and my current investigation into the nature of the Caiman crocodilus subspecies, caiman taxonomy has achieved some degree of stability, as most crocodilian biologists accept the names of the dwarf caimans and the common caiman. On the other hand, in the absence of a universally-accepted phylogenetic-based taxonomic system (and a pragmatic viewpoint dictates that such an absence will always exist), stability in terms of the number of caimans recognized by specific or subspecific nomenclature will remain elusive.

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As more and more systematists come to accept the relatively new ideas about

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Journal of Herpetology 42(4):768-772. 2008 doi: 10.1670/07-306R1.1

Feeding Behavior of Two Sympatric Caiman Species, Melanosuchus niger and Caiman crocodilus, in the Brazilian Amazon Boris Marioni1,2, Ronis Da Silveira3, William E. Magnusson4, and John Thorbjarnarson5 1

Instituto Piagaçu, Rua UZ, Quadra Z, Numero 8, Conjunto Morada do Sol, Aleixo, 69060000, Manaus/AM, Brazil [email protected]

3

Departamento de Biologia, Instituto de Ciências Biológicas, Universidade Federal do Amazonas, Rua General Rodrigo Otávio Numero 3000, 69.077-000, Manaus-AM, Brazil [email protected]

4

Coordenação de Pesquisas em Ecologia, Instituto Nacional de Pesquisas da Amazônia, CP 478, 69011-970, Manaus-AM, Brazil [email protected]

5

Wildlife Conservation Society, PO Box 357625, Gainesville, Florida 32635-762, USA [email protected]

2

Corresponding Author.

Abstract We studied the feeding behaviors of two sympatric species of caimans (Melanosuchus niger and Caiman crocodilus) during the dry season in the Mamirauá Sustainable Development Reserve, Amazonas State, Brazil. Observations were made in 50 × 13 m plots located along the land-water interface. We investigated the influence of interspecific density and the effects of temperature and water depth on the feeding behaviors of both species. We identified three principal categories of feeding behavior: trapping (with the body perpendicular to the shore, the caiman captures prey swimming close to the shore), active search (with the head under the water, the caiman searches for benthic prey), and jumping (leaping partially out of the water and capturing fish or other under water 133

invertebrates prey). Using multiple linear regression, we found that water temperature had a negative effect on trapping by M. niger; and water depth did not affect feeding behaviors in either species. Density of M. niger did not affect either the density or the frequency of feeding by C. crocodilus. Results suggest that environmental factors have little influence on the feeding behaviors of the caimans we studied, and there is probably little interspecific competition for food during the dry season. Accepted: April 16, 2008

Caimans are abundant apex predators in the Neotropics and consume a variety of terrestrial and aquatic prey (Magnusson et al. 1987; Thorbjarnarson, 1993a; Da Silveira and Magnusson, 1999; Horna et al., 2001). The feeding behaviors of caimans have previously been studied in seasonally flooded savannas in the Venezuelan Llanos (Ayarzagüena, 1983; Thorbjarnarson, 1990a, 1993b) and the Brazilian Pantanal (Schaller and Crawshaw, 1982; Olmos and Sazima, 1990). However, little is known about the feeding behavior of caimans in the forested parts of the Amazon basin. Melanosuchus niger is the largest Amazonian predator (Ross and Magnusson, 1989), and males of this species can exceed 4 m in length (Ross, 1998). Males of Caiman crocodilus can reach 2.5 m of total length (Ross, 1998), but individuals of this size are rare in the Brazilian Amazon (Da Silveira and Thorbjarnarson, 1999; Da Silveira, 2001). In many parts of the Amazon basin, these two species are broadly sympatric, and studies of feeding behavior may help us understand the ecological relationships between these caimans. Our study was undertaken during the dry season and examined feeding behaviors of Black Caiman (M. niger) and Spectacled Caiman (C. crocodilus) in the Mamirauá Sustainable Development Reserve in the western Brazilian Amazon. Highest densities of these species in the Amazon basin are found in this reserve. Large and sympatric populations have been effectively protected from hunting for the past 10 years offering a unique opportunity to study the behavior of these species without significant human interference (Da Silveira, 2002). The specific questions addressed in this study were (1) Does the abundance of M. niger affect density and the feeding behaviors of C. crocodilus? and (2) do air and water temperature or water depth affect the feeding behavior of either species?

Materials and Methods The study was carried out during the annual dry season (24 September and 2 November 2001) in the southeastern portion (03°08′S to 64°45′W and 02°36′S to 67°13′W) of the 134

Mamirauá Sustainable Development Reserve (MSDR), Brazilian Amazon. The MSDR covers 1,124,000 ha of seasonally inundated varzea forest at the confluence of the Solimões (Amazon) and Japurá Rivers (Ayres, 1993). Caiman feeding behavior was observed in 42 plots located along the shores of the Lago Mamirauá, which is one of the largest water bodies in the MSDR. During the wet season, it is approximately 10 km long and 400 m wide (Ayres, 1993). Further observations were made along the shores of Cano Mamirauá, a 10km long channel that connects the lake to the Solimões River. Additional information on the MSDR is available from its management plan (Mamirauá, 1996, available at www.mamiraua.org.br). We carried out general ad libitum observations (Altman, 1974) for 20 h to define categories of feeding behavior. After that, we classified them into three categories: trapping, active searching, and jumping. Trapping is a passive behavior with the caimans remaining immobile, body oriented perpendicular to the shore, with the head and most of the body in shallow water and usually with at least a portion of tail on land. In this position, the caimans' body will block underwater moving prey along the shore, and caimans can capture them with a rapid lateral movement of the head and the tail. Searching is an active foraging technique with caiman moving slowly in shallow water along the shoreline and periodically submerging the head and moving it in sweeping motions from side to side in search of submerged prey. Jumping is also an active feeding behavior with caimans using their hind legs and tail to propel their body forward and partially out of the water. As observed sometimes, submerged prey (e.g., fish, crab) was captured as the caiman splashes back down into the water. A total of 42 observational plots (50 m long and 13 m wide [10 m into the water and three meters on land]) was marked with wooden sticks placed two or three days before observation began, so caimans would become accustomed to them. We carried out observations of caiman feeding behaviors from a blind 20–50 m from the plots (mostly on the same shore) and covered by a green plastic mosquito net. We undertook two observation sessions of 20 min each in each of 34 plots, with a 40-min interval between the end of the first and the beginning of the second. We used means of two sessions in each plot in the statistical analyses. Only one observation session was made in eight plots because only one or two individuals were found during the first observation session. The 76 observation sessions totaling 25 h of data collection were carried out between 0700 and 800 h. We carried out 36 observation sessions between midday and 1600 h. We did not performed nocturnal observations because artificial light would be needed and could potentially affect caiman behavior (Santiago et al., 1998). We measured air temperature at the beginning and end of observations at each plot and water temperature at 0.3 m depth and 10 m from the shore at the end of the data collection in each plot. We measured water depth at 10 m from the shore in six equidistant points along the 50-m extension of the plot, 135

and in 69% of the plots mean depth was less than 50 cm. We used mean depth and air temperature of each plot in the statistical analyses. The SVL of approximately 50% of the individuals present in each plot was visually estimated before each observation session based on the field experience of the authors (Magnusson, 1983; Da Silveira et al., 1997). Throughout all sessions, the number of individuals of each species was counted every 2 min. Immediately after each count, the number of feeding (jump and search) attempts by each species was recorded for each 2-min period. The large number of caimans in some plots did not permit quantification of individuals' feeding attempts. Also, we were unable to accurately determine the prey captured or the percentage of successful fishing attempts for any of the behaviors. The number of individuals in the characteristic trapping position along the shoreline was also noted during each 2-min period. Multiple regression analysis was used to investigate the influence of M. niger density, water and air temperatures, and depth on the feeding behavior of each species. The effect of M. niger density on C. crocodilus feeding was also investigated. Density was indexed as the maximum number of individuals counted in each plot during the 40-min observation. All analyses were carried out in the Systat 8.0 package (L. Wilkinson, SPSS Inc. Chicago, 1998).

Results The total number of both species of caimans in the 42 plots was 696; 88% were M. niger and 12% were C. crocodilus. The number of M. niger in the plots varied between zero (N = 2) and 50 individuals (Fig. 1A). In 45% of the plots, more than 15 M. niger were present. Estimated SVL (ESVL) of 276 M. niger varied between 30 and 170 cm. Forty-five percent of the observed M. niger (N = 126) were between 85 and 105 cm ESVL (Fig. 1B) size-classes, which are principally male and female subadults (Da Silveira, 2001).

enlarge figure

136

Figure 1 Observed density (A) and size structure of Melanosuchus niger (B) and Caiman crocodilus (C) in 42 sampled plots in the Mamirauá Reserve. The number of C. crocodilus in the plots varied between zero (N = 14) and nine individuals (Fig. 1A). ESVL of 54 C. crocodilus ranged between 40 and 110 cm. Fifty-seven percent of the C. crocodilus (N = 31) observed were between 65 and 85 cm ESVL (Fig. 1C), which corresponds to adult females and subadult males (Thorbjarnarson, 1994). No hatchlings (SVL < 20 cm) of either species were observed. In total, we observed 10 jumps and 16 active searches by C. crocodilus and 252 jumps and 244 active searches by M. niger, suggesting these two feeding behaviors are used in similar proportion by both species. The density of M. niger significantly affected the frequency of the three feeding behaviors observed for this species (Table 1A). The relationship between this variable and the three feeding behaviors was linear, and more M. niger number in a plot resulted in more feeding attempts recorded. However, density of M. niger did not significantly affect any of the three feeding behaviors carried out by C. crocodilus (Table 1B) or the number of C. crocodilus present in each plot (Table 1C).

Table 1 Summary of the multiple regression analyses: effect of three independent variables on (A) Melanosuchus niger and (B) Caiman crocodilus feeding behaviors and (C) C. crocodilus density in the 42 plots observed in the Mamirauá Reserve. Air temperature varied between 25 and 37°C (mean = 30.8°C, SD = 3.3) and water temperature varied from 29–38°C (mean = 32.8°C, SD = 2.4). Air temperature was highly correlated to mean water temperature (r = 0.7) and was not included in the models. Water depth varied between almost zero and 220 cm (mean = 46 cm, SD = 42.2). The only environmental factor found to influence feeding behavior was water temperature, which was negatively correlated with trapping behavior of M. niger (P = 0.006; Fig. 2). Water depth did not significantly affect any of the three feeding behavior of either species (Table 1).

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Figure 2 Partial regression between the water temperature and the number of Melanosuchus niger carrying out the trapping behavior. Some numbers of the axes are negatives because the partial regression represents deviations from the expected result if all others variables were held constant at their observed means.

Discussion Crocodilians are generalist feeders, eating a wide variety of animal prey (Lang, 1987). Black Caiman and Spectacled Caiman principally feed on insects (coleoptera), spiders, crabs, snails, fishes, and rarely other vertebrates as birds, mammals, and reptiles (Magnusson et al. 1987; Thorbjarnarson 1993a; Da Silveira and Magnusson 1999; Horna et al. 2001). Although some crocodilians, such as the Narrow-Snouted Gharial (Gavialis gangeticus) or the Australian Freshwater Crocodile (Crocodylus johnsoni), have morphological specializations for the capture of aquatic prey; the Broad-Snouted Caiman (Caiman latirostris) depends largely on behavioral specializations (Thorbjarnarson, 1990b, 1993b; Olmos and Sazima, 1990). Crocodilians, including C. crocodilus, have been reported to use a fish trapping technique that uses the body and tail to trap prey against the shore (Pooley and Gans, 1976; Schaller and Crawshaw, 1982; Thorbjarnarson, 1993b). We never observed this trapping technique being used by M. niger in the Mamirauá Reserve; and occasionally we saw a similar behavior in C. crocodilus, when the caiman was swimming parallel to the shore and used a very slow movement of the tail to drag water throughout its open mouth obviously trying to catch small fish. However, we did not quantify this foraging technique because it was not observed during the initial ad libitum observations. Water temperature was the only environmental factors that influenced M. niger trapping behavior in the Mamirauá Reserve. During this feeding behavior, the individuals stay immobile with the whole dorsal part of the body exposed to the sun, and probably during the hottest hours of the day, it becomes difficult to maintain an ideal body temperature. Thus, caimans stop this behavior and submerge most of their body to regulate their body temperature, as it was already observed in C. crocodilus (J. W. Lang, Thermal ecology and social behaviors of Caiman crocodilus in the Llanos of Venezuela. Progress Report to the National Zoological Park, Smithsonian Institution, unpubl. data, 1977). Water temperature does not have any effects on jumping and searching behaviors of both species. Probably 138

overheating is easier to avoid because during these behaviors caimans' body surface were mostly submerged. Water depth did not affect any of the behaviors we investigated. However, the study was undertaken during the dry season, and water depth in our study plots was shallow and varied little. Probably the three feeding behaviors described in this study can only be performed in shallow water. When water levels rise more than 10 m during the annual wet season, shallow habitats are very rare in the MSDR, and we presume the caimans change their foraging techniques or may simply stop eating during this period of the year, as apparently happens in the Anavilhanas Archipelago (Da Silveira and Magnusson, 1999). We did not observe caiman fishing while floating on the water surface as observed in Venezuela and the Brazilian Pantanal (Schaller and Crawshaw, 1982; Thorbjarnarson, 1993b; Olmos and Sazima, 1990). Also the weir fishing technique (Schaller and Crawshaw, 1982; Thorbjarnarson, 1993b) used in narrow canals to capture fish swimming upstream was not seen in the MSDR. Other studies have found that jumping has a very low success rate in capturing fish (M. A. Staton and J. R. Dixon, Breeding biology of the Spectacled Caiman, Caiman crocodilus crocodilus, in the Venezuelan Llanos, Wildlife Research Report Vol. 5, unpubl. data, 1977; Thorbjarnarson, 1993b). How jumping may help capture prey is not well understood, but it may serve to disorient aquatic prey and facilitate anticipation of prey perception by other caimans. We periodically observed that, when one M. niger jumped, the behavior appeared to be contagious and nearby individuals would also start jumping, and this may be some form of social facilitation or group feeding behavior. In Venezuelan Llanos, M. A. Staton and J. R. Dixon (Breeding biology of the Spectacled Caiman, Caiman crocodilus crocodilus, in the Venezuelan Llanos, Wildlife Research Report Vol. 5, unpubl. data, 1977) considered jumping behavior as a sexual display that was part of the reproductive behavior in C. crocodilus and that it could have an alimentary function too. The present study was not carried out during the caimans mating period (Da Silveira, 2001); thus, we did not consider jumping as part of the reproductive behavior in the Mamirauá Reserve but primary as a feeding behavior. Preliminary research suggested that M. niger can affect the ecology of C. crocodilus (Magnusson, 1982; Magnusson and Rebelo, 1983). In our study, M. niger density did not affect either the density or feeding behavior of C. crocodilus, suggesting there may be little interspecific competition for food during the dry season in the Mamirauá Reserve and probably most of the Amazonian flooded forests.

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Acknowledgments This study was supported by the Conselho Nacional de Desenvolvimento Cientifico e Tecnológico do Ministério da Ciência e Tecnologia (CNPq/MCT do Brasil), Sociedade Civil Mamirauá (SCM), Instituto de Desenvolvimento Sustentável Mamirauá (IDSM), the European Union and the Wildlife Conservation Society (WCS). It was part of the graduate thesis of Boris Marioni at the Université de Neuchâtel (UniNe), Switzerland. The Wüthrich Fund (Switzerland) paid for Boris Marioni's plane ticket from Europe and some equipment. We would like to thank the professors of the UniNeSwitzerland, Claude Mermod and Louis-Félix Bersier for their help during the study. Special thanks to all the inhabitants of the Mamirauá Reserve; without them, this study would not have been possible.

Literature Cited Altman, J. 1974. Observational study of behavior: sampling methods. Behaviour 49:227– 267. CrossRef, Medline Ayarzagüena, J. 1983. Ecologia del caiman de anteojos o baba (Caiman crocodilus L.) en los Llanos de Venezuela. Doñana 10:1–136.

Ayres, J. M. 1993. As Matas de Várzea do Mamirauá. CNPq: Sociedade Civil Mamirauá. Brasilia, Distrito Federal, Brazil.

Da Silveira, R. 2001. Monitoramento, crescimento e caça de jacaré-açu (Melanosuchus niger) e de jacaré-tinga (Caiman crocodilus crocodilus). Unpubl. Ph.D. diss., Instituto Nacional de Pesquisa da Amazônia (INPA), Manaus, Brazil.

Da Silveira, R. 2002. Conservação e manejo do jacaré açu (Melanosuchus niger) na Amazônia brasileira. In Verdade, L. M. and A. Larriera , editors. Conservação e Manejo de Jacarés e Crocodilos da América Latina—La Conservación y el Manejo de Caimanes y Cocodrilos de América Latinal. 61–78.Piracicaba, São Paulo, São Paulo, Brazil.

Da Silveira, R. and W. E. Magnusson . 1999. Diets of Spectacled and Black Caiman in the Anavilhanas Archipelago, Central Amazonia, Brazil. Journal of Herpetology 33:181–192. CrossRef

Da Silveira, R. and J. Thorbjarnarson . 1999. Conservation implications of commercial hunting

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of Black Caiman and Spectacled Caiman in the Mamirauá Sustainable Development Reserve, Brazil. Biological Conservation 88:103–109. CrossRef, CSA

Da Silveira, R. , W. E. Magnusson , and Z. Campos . 1997. Monitoring the distribution, abundance and breeding areas of Caiman crocodilus crocodilus and Melanosuchus niger in the Anavilhanas Archipelago, Central Amazonia, Brazil. Journal of Herpetology 31:514–520. CrossRef

Horna, J. V. , R. Cintra , and P. V. Ruesta . 2001. Feeding ecology of Black Caiman Melanosuchus niger in a western Amazonian forest: the effects of ontogeny and seasonality on diet composition. Ecotropica 7:1–11.

Lang, J. W. 1987. Crocodilian behavior: implications for management. In Webb, G. J. W. , S. C. Manolis , and P. J. Whitehead , editors. Wildlife Management: Crocodiles and Alligators. 273–294.Surrey Beatty and Sons. Canberra, Australia Capital Territory, Australia.

Magnusson, W. E. 1982. Biological aspects of the conservation of Amazonian crocodilians in Brazil. In. Crocodiles Proceedings of the 5th Working Meeting of the Crocodile Specialist Group. 108–116.IUCN/SSC. Gland, Switzerland.

Magnusson, W. E. 1983. Size estimates of crocodilians. Journal of Herpetology 17:86–88. CrossRef, CSA

Magnusson, W. E. and G. H. Rebelo . 1983. Brazilian crocodiles: problems of conservation in a multispecies system. Zimbabwe Science News 17:56–57.

Magnusson, W. E. , E. V. Silva , and A. P. Lima . 1987. Diets of Amazonian crocodilians. Journal of Herpetology 21:85–95. CrossRef, CSA

Olmos, F. and I. Sazima . 1990. A fishing tactic in floating Paraguayan caiman: the crossposture. Copeia 1990:875–877. CrossRef

Pooley, C. and C. Gans . 1976. The Nile crocodile. Scientific American 234:114–124. Medline

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Ross, J. P. 1998. Crocodile Specialist Group IUCN/SSC (eds.) Crocodiles: Status Survey and Conservation Action Plan. 2nd ed. Gland, Switzerland.

Ross, C. A. and W. E. Magnusson . 1989. Living crocodilians. In Ross, C. A. and S. Garnett , editors. Crocodiles and Alligators. 58–73.Merehurst Press. London.

Santiago, R. , A. Vallejo , and E. Assanza . 1998. Human influence on the wariness of Melanosuchus niger and Caiman crocodilus in Cuyabeno, Ecuador. Journal of Herpetology 32:320–324. CrossRef, CSA

Schaller, G. B. and P. G. Crawshaw . 1982. Fishing behavior of Paraguayan caiman (Caiman crocodilus). Copeia 1982:66–72. CrossRef

Thorbjarnarson, J. 1990a. Ecology and Behavior of the Spectacled Caiman (Caiman crocodilus) in the Central Venezuelan Llanos. Unpubl. Ph.D. diss., University of Florida, Gainesville.

Thorbjarnarson, J. 1990b. Notes on the feeding behavior of the Gharial (Gavialis gangeticus) under semi-natural conditions. Journal of Herpetology 24:99–100. CrossRef, CSA

Thorbjarnarson, J. 1993a. Diet of the Spectacled Caiman (Caiman crocodilus) in the central Venezuelan Llanos. Herpetologica 19:108–117.

Thorbjarnarson, J. 1993b. Fishing behavior of Spectacled Caiman in Venezuelan Llanos. Copeia 1993:1166–1171. CrossRef

Thorbjarnarson, J. 1994. Reproductive Ecology of the Spectacled Caiman (Caiman crocodilus) in the Venezuelan Llanos. Copeia 1994:907–919. CrossRef

Title

Biomechanics of the rostrum in crocodilians: a comparative analysis using finite-element modeling Author/Creator McHenry, Colin R.

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Author/Creator Clausen, Philip D. Author/Creator Daniel, William J. T. Author/Creator Meers, Mason B. Author /Creat or Pendharkar, Atul Descri ption This article reports the use of simple beam and finite-element models to investigate

the

relationship

between

rostral

shape

and

biomechanical

performance in living crocodilians under a range of loading conditions. Load cases corresponded to simple biting, lateral head shaking, and twist feeding behaviors. The six specimens were chosen to reflect, as far as possible, the full range of rostral shape in living crocodilians: a juvenile Caiman crocodilus, subadult Alligator mississippiensis and Crocodylus johnstoni, and adult Caiman crocodilus, Melanosuchus niger, and Paleosuchus palpebrosus. The simple beam models were generated using morphometric landmarks from each specimen. Three of the finite-element models, the A. mississippiensis, juvenile Caiman crocodilus, and the Crocodylus johnstoni, were based on CT scan data from respective specimens, but these data were not available for the other models and so these the adult Caiman crocodilus, M. niger, and P. palpebrosus - were generated by morphing the juvenile Caiman crocodilus mesh with reference to threedimensional linear distance measured from specimens. Comparison of the mechanical performance of the six finite-element models essentially matched results of the simple beam models: relatively tall skulls performed best under vertical loading and tall and wide skulls performed best under torsional loading. The widely held assumption that the platyrostral (dorsoventrally flattened) crocodilian skull is optimized for torsional loading was not supported by either simple beam theory models or finite-element modeling. Rather than being purely optimized against loads encountered while subduing and processing food, the shape

of

the

crocodilian

rostrum

may

be

significantly

affected

by

the

hydrodynamic constraints of catching agile aquatic prey. This observation has important implications for our understanding of biomechanics in crocodilians and other aquatic reptiles.

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R Anatomical Record Part A: Discoveries in Molecular Cellular and Evolutionary Biology Vol. 288A, Issue 8, p. 827-849

http://dx.doi.org/10.1002/ar.a.20360

2006

John Wiley

crocodiles

skull biomechanics

finite-element analysis

feeding

hydrodynamics

aquatic/marine tetrapods

comparative modeling

journal article

http://hdl.handle.net/1959.13/26909

ISSN:1552-4884

Brazilian alligators survive extinction threat, paper says 144

Asian Economic News , Oct 28, 2002 • •

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RIO DE JANEIRO, Oct. 24 Kyodo Two alligator species in Brazil that are threatened with extinction may survive as their numbers are increasing, a newspaper reported Wednesday. The populations of the black caiman (melanosuchus niger), the largest of the four Amazonian alligator species, and the broad-snouted caiman (caiman latirostins), found in the Pantanal Wetlands in central Brazil, have soared chiefly because of breeding in captivity, according to environmentalists quoted by the daily O Estado de Sao Paulo. The two species of alligators are illegally hunted in the wilderness with harpoons and rifles. The commercial value of a large-size alligator skin is approximately $50, the daily said.

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The two species are listed in the Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES), an agreement under which governments are pledged to ensure that trade in specimens of wild animals and plants does not threaten their existence. ''We believed that in the 1980s the caiman populations were smaller, but we have concluded they are more abundant than we thought,'' the newspaper quoted agronomist Luciano Verdade as saying. The main threat for the survival and preservation of the two species is not hunting, but the loss of their natural habitat, chiefly in the Pantanal Wetlands, according to Verdade. The agronomist recommended the expansion of extensive breeding of alligators in the wetlands as a strategy to curb the expansion of cattle growing in the region. The Brazilian Wildlife Law of 1967 authorizes the breeding of wild animals for commercial purposes and environmentalists have said this practice has been decisive in the expansion of the alligator populations. The environmentalists have gathered in Sao Paulo for a workshop sponsored by the federal Environment Agency (Ibama) to debate the private breeding of the two species threatened with extinction. The agency has registered 75 ranching operations that produce alligator skins and some of them already have started exports of the product.

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The caiman was abundant in the rivers, lagoons and swamps of tropical South America, but extensive commercial hunting that began in the 1920s has relegated them to ever-dwindling islands of residual populations.

COPYRIGHT 2002 Kyodo News International, Inc. COPYRIGHT 2008 Gale, Cengage Learning

Abstract The effect of mark-recapture experiments on the wariness of Caiman crocodilus and Melanosuchus niger in two lakes in Amazonian Ecuador was examined. Three experiments were conducted with five, seven, and 10 sampling replicates, respectively. Each sampling replicate consisted of one nocturnal spotlight count around the lake, during which caimans were captured, marked, and released. There were negative correlations between the number of individuals seen in each sampling replicate and sampling replicate sequence in both lakes and both species. In one lake, there was a positive correlation between the percentage of wary caimans and the sequence of sampling replicates. Our findings indicate that observation and capture, even if harmless, affect the spatial distribution and wariness of crocodilian populations. /// Examinamos el efecto de la conducción de experimentos de captura-recaptura en la cautela de Caiman crocodilus y Melanosuchus niger en dos lagunas de la Amazonía Ecuatoriana. Se llevó a cabo tres experimentos con cinco, siete y 10 muestreos respectivamente. Cada muestreo consistió en un conteo nocturno al rededor de la laguna a lo largo del cual se capturó, marcó y liberó caimanes. En ambas especies se observó correlaciones negativas entre el número de individuos vistos en cada muestreo y la secuencia de los muestreos. En una de las dos lagunas hubo una correlación positiva entre el porcentaje de caimanes ariscos y la secuencia de los muestreos. Los resultados de este estudio indican que influencias humanas, incluso si son inofensivas, afectan la distribución y cautela de las poblaciones de cocodrilianos.

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Journal of Herpetology 41(1):164-167. 2007 doi: 10.1670/0022-1511(2007)41[164:NOTBCM]2.0.CO;2

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Nesting of the Black Caiman (Melanosuchus Niger) in Northeastern Ecuador Francisco VillamarÍn-Jurado1,2 and Esteban Suárez3 1

Escuela de Ciencias Biológicas, Pontificia Universidad Católica del Ecuador, Quito, Ecuador

3

Wildlife Conservation Society, Ecuador Program, Quito, Ecuador

2

Corresponding Author. Present addres: Pasaje Kodaly D-52 y Luis de Beethoven, Quito, Ecuador; E-mail: [email protected]

Abstract Seven Black Caiman (Melanosuchus niger) nests were located and monitored at Limoncocha and Añangu lagoons (northeastern Ecuador), between October 2002 and March 2003. Melanosuchus niger nesting coincided with the annual low water level season in the Ecuadorian Amazon. Mean number of eggs per nest was 28 and 34 eggs at Limoncocha and Añangu, respectively. Egg chamber temperature was monitored in two nests during the incubation period and showed no relationship with external air temperature, suggesting that the nests have their own heating sources. Mean hatching success was 42.4%, and flooding of the nests was identified as the main cause of egg mortality (29% of all the eggs). Accepted: October 12, 2006

Literature Cited Allsteadt, J. 1994. Nesting ecology of Caiman crocodilus in Caño Negro, Costa Rica. Journal of Herpetology 28:12–19. CrossRef, CSA Asanza, E. 1985. Distribución, biología reproductiva y alimentación de cuatro especies de Alligatoridae, especialmente Caiman crocodilus en la Amazonía del Ecuador. Unpubl. bachelor's thesis. Pontificia Universidad Católica del Ecuador. Quito, Ecuador. Brazaitis, P. , G. H. Rebêlo , C. Yamashita , E. A. Odierna , and M. E. Watanabe . 1996. Threats to Brazilian crocodilian populations. Oryx 30:275–284. CSA Campos, Z. 1993. Effect of habitat on survival of eggs and sex ratio of hatchlings of Caiman crocodilus yacare in the Pantanal, Brazil. Journal of Herpetology 27:127–132. CrossRef, CSA

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Cintra, R. 1988. Nesting ecology of the Paraguayan Caiman (Caiman yacare) in the Brazilian pantanal. Journal of Herpetology 22:219–222. CrossRef, CSA Da Silveira, R. and W. E. Magnusson . 1999. Diets of Spectacled and Black Caiman in the Anavilhanas archipelago, central Amazonia. Brazilian Journal of Herpetology 33:181–192. CrossRef Da Silveira, R. , W. E. Magnusson , and Z. Campos . 1997. Monitoring the distribution, abundance and breeding areas of Caiman crocodilus crocodilus and Melanosuchus niger in the Anavilhanas archipelago, central Amazonia, Brazil. Journal of Herpetology 31:514–520. CrossRef Endara, A. and F. VillamarÍn-Jurado . 2005. Caimán Negro (Melanosuchus niger). In Carrillo, E. , S. Aldás , M. Altamirano , F. Ayala , D. Cisneros , A. Endara , C. Márquez , M. Morales , F. Nogales , P. Salvador , M. L. Torres , J. Valencia , F. Villamarín , M. Yánez , and P. Zárate , editors. eds. Lista Roja de Reptiles del Ecuador. 20. Fundación Novum Millenium, UICN-Sur, UICN-Comité Ecuatoriano, Ministerio de Educación y Cultura. Serie Proyecto PEEPE. Quito, Ecuador. Herron, J. C. 1991. Growth rates of Black Caiman, Melanosuchus niger and Spectacled Caiman, Caiman crododilus, and the recruitment of breeders in hunted caiman populations. Biological Conservation 55:103–113. CrossRef, CSA Herron, J. C. 1994. Body size, spatial distribution, and microhabitat use in the caimans, Melanosuchus niger and Caiman crododilus, in a Peruvian lake. Journal of Herpetology 28:508–513. CrossRef, CSA Herron, J. C. , L. H. Emmons , and J. E. Cadle . 1990. Observations on reproduction in the Black Caiman, Melanosuchus niger. Journal of Herpetology 24:314–316. CrossRef, CSA Kushlan, J. A. and T. Jacobsen . 1990. Environmental variability and the reproductive success of Everglades Alligators. Journal of Herpetology 24:176–184. CrossRef, CSA Magnusson, W. E. , A. P. Lima , and R. M. Sampaio . 1985. Sources of heat for nests of Paleosuchus trigonatus and a review of crocodilian nest temperatures. Journal of Herpetology 19:199–207. CrossRef, CSA Magnusson, W. E. , A. P. Lima , J. M. Hero , M. Sanaiotti , and M. Yamakoshi . 1990. Paleosuchus trigonatus nests: sources of heat and embryo sex ratios. Journal of Herpetology 24:397–400. CrossRef, CSA

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Medem, F. 1983. Los Crocodylia de Sur América. Venezuela, Trinidad-Tobago, Guyana, Suriname, Guyana Francesa, Ecuador, Perú, Bolivia, Brasil, Paraguay, Argentina, Uruguay. Volumen II. Universidad Nacional de Colombia y Colciencias. Bogotá, Colombia. Palacios, W. , C. Cerón , R. Valencia , and R. Sierra . 1999. Las formaciones naturales de la Amazonía del Ecuador. In Sierra, R. , editor. ed. Propuesta Preliminar de un Sistema de Clasificación de Vegetación para el Ecuador Continental. 109–119.Proyecto INEFAN/GEF-BIRF y Ecociencia. Quito, Ecuador. Rebêlo, G. H. and L. Lugli . 2001. Distribution and abundance of four caiman species (Crocodylia: Alligatoridae) in Jaú National Park, Amazonas, Brazil. Revista de Biología Tropical 49:1096–1109. VillamarÍn-Jurado, F. 2006. Anidación y patrones de uso de hábitat del Caimán Negro, Melanosuchus niger (Crocodylia: Alligatoridae), en dos localidades de la Amazonía ecuatoriana. Unpubl. bachelor's thesis,. Pontificia Universidad Católica del Ecuador. Quito, Ecuador.

Titre du document / Document title Genetic structure, population dynamics, and conservation of Black caiman (Melanosuchus niger) Auteur(s) / Author(s) DE THOISY Benoit (1) ; HRBEK Tomas (2 3) ; PIRES FARIAS Izeni (2) ; RANGEL VASCONCELOS William (2) ; LAVERGNE Anne (1 4) ; Affiliation(s) du ou des auteurs / Author(s) Affiliation(s) (1) Association Kwata, BP 672, 97335 Cayenne, GUYANE FRANCAISE (2) Universidade Federal do Amazonas (UFAM), Departamento de Ciências Biológicas, Laboratório de Evolução e Genética Animal, Mini Campus ICB, Au. Gen. Rodrigo Octávio Jordâo Ramos, 3000 -Coroado, CEP 69077-000, Manaus, AM, BRESIL (3) University of Puerto Rico -Rio Piedras, Biology Department, Box 23360, UPR Station, San Juan, 00931-3360, PORTO RICO (4) Institut Pasteur de la Guyane, BP 6010, 97306 Cayenne, GUYANE FRANCAISE Résumé / Abstract Microsatellite DNA polymorphisms were screened in seven populations of the largest Neotropical predator, the Black caiman Melanosuchus niger (n = 169), originating from Brazil, French Guiana and Ecuador. Eight loci were used, for a total of 62 alleles. The Ecuadorian population had the lowest number of alleles, heterozygosity and gene diversity; populations of the Guianas region exhibited intermediate diversities; highest values were recorded in the two populations of the Amazon and Rio Negro. During the last century Melanosuchus populations have been reduced to 1-10% of their initial levels because of hunting pressure, but no strong loss of genetic diversity was observed. Both the inter-locus g-test and the Pk distribution suggested no recent important recovery and/or expansion of current populations. On a global scale, the inter-population variation of alleles indicated strong differentiation (FST = 0.137). Populations were significantly isolated from each other, with rather limited gene flow; however, these gene flow levels are sufficiently high for recolonization processes to effectively act at regional scales. In French Guiana, genetic structuring is observed between populations of two geographically close but ecologically distinct habitats, an estuary and a swamp. Similar divergence is observed in Brazil between geographically proximate "black water" and "white water" populations. As a consequence, the conservation strategy of the Black caiman should include adequate ecosystem management, with strong attention to preservation of habitat integrity. Distribution of genetic diversity suggests that current populations originated from the central Amazonian region. Dispersal of the species may thus have been deeply influenced by major climatic changes during the Holocene/Pleistocene period, when the Amazonian hydrographic networks were altered. Major ecological changes such as glaciations, marine transgressions and a hypothesized presence of an Amazonian Lake could have resulted in extension of Black caiman habitats followed by isolation. Revue / Journal Title Biological conservation ISSN 0006-3207 CODEN BICOBK Source / Source 2006, vol. 133, no4, pp. 474-482 [9 page(s) (article)] (1 p.1/2) Langue / Language Anglais

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Editeur / Publisher Elsevier, Oxford, ROYAUME-UNI (1968) (Revue) Mots-clés anglais / English Keywords Vertebrata ; Reptilia ; Crocodilia ; Africa ; Polymorphism ; Microsatellite DNA ; Niger ; Environmental protection ; Conservation ; Population dynamics ; Population structure ; Population genetics ; Mots-clés français / French Keywords Crocodylidae ; Vertebrata ; Reptilia ; Crocodilia ; Afrique ; Caiman ; Polymorphisme ; DNA microsatellite ; Niger ; Protection environnement ; Conservation ; Dynamique population ; Structure population ; Génétique population ; Mots-clés espagnols / Spanish Keywords Vertebrata ; Reptilia ; Crocodilia ; Africa ; Polimorfismo ; DNA microsatélite ; Niger ; Protección medio ambiente ; Conservación ; Dinámica población ; Estructura población ; Genética población ; Mots-clés d'auteur / Author Keywords Black caiman ; Melanosuchus niger ; DNA microsatellite polymorphism ; Population dynamics ; Localisation / Location INIST-CNRS, Cote INIST : 14169, 35400014510516.0070

Vasconcelos WR, Hrbek T, Da Silveira R, De Thoisy B, Ruffeil LA, Farias IP. Departamento de Ciências Biológicas, Laboratório de Evolução e Genética Animal, Universidade Federal do Amazonas (UFAM), Manaus, AM, Brazil.

We assessed the spatial distribution of the genetic variability of Melanosuchus niger from 11 localities in South America using 1,027 base pairs of the mitochondrial cytochrome b gene. Screening 132 animals, we found 41 haplotypes, high values of genetic diversity, low values of nucleotide diversity and significant deviations from neutral expectation of allelic frequencies in some localities. Mantel test and nested-clade analysis indicated that isolation-by-distance was an important population dynamic for the species as a whole. Wright's fixation indexes analyses showed that hydrogeographically separated populations from French Guiana together with Amapá state population in Brazil are genetically differentiated from all other populations that are found in the Amazon drainage basin. These indexes also disclosed that the population from Ecuador is genetically differentiated in relation to the populations from Brazil, Peru and French Guiana. Within the Amazon Basin little differentiation exists, and genetic and geographic distances are not correlated. Demographic data as well as population genetic data suggest that M. niger is recovering in some protected regions. However, part of this apparent recovery may be owing to the movement of animals into protected regions. (c) 2008 Wiley-Liss, Inc.

Distribution and abundance of four caiman species (Crocodylia: Alligatoridae) in Jaú National Park, Amazonas, Brazil. Rebêlo GH, Lugli L. Instituto Nacional de Pesquisas da Amazônia, Coordenação de Pesquisas em Ecologia, Caixa Postal 478, 69011-970 Manaus-AM, Brazil. [email protected]

Jaú National Park is a large rain forest reserve that contains small populations of four caiman species. We sampled crocodilian populations during 30 surveys over a period of four years in five study areas. We found the mean abundance of caiman species to be very low (1.0 +/- 0.5 caiman/km of shoreline), independent of habitat type (river, stream or lake) and season. While abundance was almost equal, the species'

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composition varied in different waterbody and study areas. We analysed the structure similarity of this assemblage. Lake and river habitats were the most similar habitats, and inhabited by at least two species, mainly Caiman crocodilus and Melanosuchus niger. However, those species can also inhabit streams. Streams were the most dissimilar habitats studied and also had two other species: Paleosuchus trigonatus and P. palpebrosus. The structure of these assemblage does not suggest a pattern of species associated and separated by habitat. Trends in species relationships had a negative correlation with species of similar size, C. crocodilus and P. trigonatus, and an apparent complete exclusion of M. niger and P. trigonatus. Microhabitat analysis suggests a slender habitat partitioning. P. trigonatus was absent from river and lake Igapó (flooded forest), but frequent in stream Igapó. This species was the most terrestrial and found in microhabitats similar to C. crocodilus (shallow waters, slow current). Melanosuchus niger inhabits deep, fast moving waters in different study areas. Despite inhabiting the same waterbodies in many surveys, M. niger and C. crocodilus did not share the same microhabitats. Paleosuchus palpebrosus was observed only in running waters and never in stagnant lake habitats. Cluster analysis revealed three survey groups: two constitute a mosaic in floodplains, (a) a cluster with both M. niger and C. crocodilus, and another (b) with only C. crocodilus. A third cluster (c) included more species, and the presence of Paleosuchus species. There was no significant difference among wariness of caimans between disturbed and undisturbed localities. However, there was a clear trend to increase wariness during the course of consecutive surveys at four localities, suggesting that we, more than local inhabitants, had disturbed caimans. The factors that are limiting caiman populations can be independent of human exploitation. Currently in Amazonia, increased the pressure of hunting, habitat loss and habitat alteration, and there is no evidence of widespread recovery of caiman populations. In large reserves as Jaú without many disturbance, most caiman populations can be low density, suggesting that in blackwater environments their recovery from exploitation should be very slow.

Ethyl-branched aldehydes, ketones, and diketones from caimans (Caiman and Paleosuchus; Crocodylia, Reptilia). Krückert K, Flachsbarth B, Schulz S, Hentschel U, Weldon PJ. Institut für Organische Chemie, Technische Universität Braunschweig, Hagenring 30, 38106 Braunschweig, Germany.

Secretions from the paracloacal glands of alligators (Alligator spp.) and caimans (Caiman spp., Melanosuchus niger, and Paleosuchus spp.) were examined by GC-MS. The secretions of the common caiman (C. crocodilus), the broad-snouted caiman (C. latirostris), the yacare caiman (C. yacare), the dwarf caiman (P. palpebrosus), and the smooth-fronted caiman (P. trigonatus) yielded a new family of 43 aliphatic carbonyl compounds that includes aldehydes, ketones, and beta-diketones with an ethyl branch adjacent to the carbonyl group. The identification of these glandular components and the syntheses and stereochemical investigations of selected compounds are described.

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Melanosuchus Niger Melanosuchus Niger is also known as the Black caiman are endemic to Bolivia, Brazil, Colombia, Ecuador, French Guiana, Guyana, Peru, Venezuela and are found in various freshwater habitats like slow-moving rivers, streams, lakes and flooded savannah and wetlands. It belongs to the kingdom of Animalia, with the phylum of Chordata, from the class of Sauropsida, by the order of Crocodilia.

In appearance these are the largest species among its family and a normal adult grow to a length of 4-6 metres with a dark colouration where its lower jaw has grey banding and pale yellow or white bands are present across the flanks of the body and this banding fades with age. It is structurally dissimilar in its shape of the skull and has distinctly larger eyes, with a relatively narrow snout along with a bony ridge extending from above the eyes down the snout. These feed on fish, piranhas, catfish and aquatic vertebrates like large Capybara rodents and is more a terrestrial hunter and very active at nights and is famous for its sharpest sight and hearing capability. These lay about 30-60 eggs and hatching takes about 40-90 days.

Anaconda vs Alligator: anacondas are known for killing other large reptiles such as the Melanosuchus niger (black caiman), and alligators are smaller then these, which would mean the constrictor would have the advantage. In shallow waters, anacondas are nearly invincible, however the largest species of crocodilians such as the Nile and Saltwater crocodiles would be formidable opponents, and perhaps emerge victors.

BLACK CAIMAN NATURAL HISTORY APPEARANCE Like a monster from the age of the dinosaurs, the primitive-looking black caiman (Melanosuchus niger) inspires fear and dread. Also called jacaré, it could be mistaken for the well-known American alligator and belongs in the same taxonomic family, Alligatoridae. It is the largest member of the family, ranking among the biggest crocodilians. It averages 10 to 13 feet (3 to 4 meters) and reaches a maximum 16.5 feet (5 meters). Indeed, this is the largest predator in South America. In appearance, the black caiman is characterized by a dark gray to black skin covered in scales (as with all reptiles), some of which are thickened and raised. The skin color may serve to camouflage the caimain during

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nocturnal hunting, while during the day, it helps absorb heat. A distinctive feature is gray banding across the lower jaw and yellow to beige bands along the sides. These markings fade as the animal ages and may be more or less absent in fully mature adults. Like the spectacled caiman, the black caiman has a bony ridge between the eyes that extends either side down the snout. In contrast, the black caiman has a relatively narrow snout and large eyes. The latter feature may be related to its nocturnal feeding habits. HABITAT AND DISTRIBUTION The black caimain inhabits remote rivers throughout lowland Amazonia. Its geographic range extends east of the Andes to the Atlantic, and north of the Brazilian Pantanal to southern Venezuela. Its range overlaps with that of the spectacled caiman, but the two species occupy quite different ecological niches. The black caiman favors areas along river banks with steep sides, among entangled roots and fallen branches. Rebelo and Lugli (2001) report that it prefers deep, fast moving waters. Juveniles are often found on floating mats of vegetation. FEEDING AND DIET Such a large animal is, as you might expect, not a fussy eater. The caiman's diet includes fish, birds and turtles. The majority of the diet is comprised piranhas, catfish and aquatic molluscs. As with other crocodilians, they ambush terrestrial animals, particularly capybara, but also peccaries and tapir when they drink at riversides or swim across a stream or swamp. Juveniles feed on small aquatic prey such as freshwater crabs, insects and other invertebrates. As they grow, the animals graduate to larger prey and sometimes hunt on dry land, mainly at night. Mature individuals occasionally attack on humans and livestock. BREEDING Few details are known of the breeding habits of wild caiman. (Perhaps unsurprisingly considering the courage needed to study the animal up close in its own domain!) In most respects, it appears similar to that of other large crocodilians. As the rivers recede and rain falls off during the dry season, the female caiman looks for a suitable spot, ususally by the side of a slow-moving river or swampy lake. The site may be out in the open or relatively hidden. Once situated, she shovels leaf litter, twigs and drying aquatic vegetation to form a large nest about 6 feet across. She then scoops out the center and lays between 30 and 65 (average 40) eggs in the mound. The eggs are oval-shaped, weighing about 5 ounces (143 g). For 40 to 100 days, she will zealously guard her horde, remaining in the vicinity to fend off egg predators. Around the beginning of the dry season, the eggs are ready to hatch, whereupon the female opens the nest, releasing the hatchlings. This is their most vulnerable stage of life. The female's interest in her offspring remains strong but she cannot protect them all. Often, many females choose nest locations close together, so if lots of hatchlings emerge together, there is a better chance at least some of them will escape and grow large enough to be relatively safe. As with other crocodilians, the gender is determined by temperature within the nest (in contrast to mammals and most other animals in which gender is determined by chromosomal arrangements). In turn, nest temperature depends on the heat of decomposing vegetation and exposure to sunlight. CONSERVATION The adult caiman is at the top of the food chain, except for humans who hunt it for food and leather. The black caiman once teemed throughout the Amazon but hunting greatly reduced numbers and it is now quite rare, less

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common than the spectacled caiman whose range overlaps. It is listed in the IUCN Red Book as Endangered. It remains locally common in isolated patches but good census data hampers efforts to establish long-term management programs. Locals sometimes justify hunting by arguing that caiman eat a large amount of their potential catch, but scientists found that the favored commercial species (such as tambaqui and pacu comprise only a small proportion of stomach contents. Economically, the species is most important as a source of meat and skin. The hunting technique is simple. Patrol a river bank at night, shining a flashlight into thick banks of reeds and riverside grasses. The eye of the caiman reflects back red, glowing like a hot coal. The hunter with a rifle needs only to shoot in the proximity of this target for the chance of a hit. Such an easy prey and lucrative trade in caiman skins for boots, purses, belts and other leather goods led to the demise of populations. Although today considered at low risk of extinction, it remains on the endangered species list. Efforts are underway to ensure the future of the black caiman. Captive breeding programs combined with controlled harvest studies suggest that the species is a good candidate for commercial farming. Such an approach would relieve pressure on wild populations and provide local people with a source of income.

Links Wikipedia: Black caiman Animal Diversity Web: Melanosuchus niger Florida Museum of Natural History: Melanosuchus niger Enchanted Learning: Black Caiman Iwokrama: Black Caiman, Prehistoric Top Predator Wildlife Conservation Society: Black Caiman Thinkquest: Caimans The Black Caiman, By Mateo Tiscali: caiman or cayman Mark O'Shea Black caiman, Melanosuchus niger Taxonomicon: Taxonomy of Melanosuchus niger ITIS: Melanosuchus niger CNN Archives: Amazonian alligator bounces back from the brink Skulls Unlimited: Black Caiman Skull National Wildlife Federation: The Hunt For Black Caiman Rebelo GH, Lugli L. (2001) Distribution and abundance of four caiman species (Crocodylia: Alligatoridae) in Jau National Park, Amazonas, Brazil. Rev Biol Trop. 49(3-4): 1095-109. National Geographic: Listing of crocodilian TV shows Mongabay: Links to black caiman websites FAO: 3.3.1 Caiman crocodilus (spectacled caiman) Mainly photos National Geographic: Black Caiman

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Alligators and Caimans Animal Pictures Archive: Black caiman Wikimedia: Melanosuchus niger visuals unlimited: eye of an adult black caiman Florida Museum of Natural History: Caiman Photo Gallery

Longevity Records: Life Spans of Mammals, Birds, Amphibians, Reptiles, and Fish

American Alligator. (larger version).

Index Search Scientific classification

Melanosuchus niger (Black caiman) Order/Family

Kingdom:

Genus/Species

Animalia Common Name

Melanosuchus niger

Black caiman Phylum:

Wild

Capt.

M/F

13.1

m

Reptilia Alligatoridae References:

Chordata

[2] Bowler, J.K., 1975. Longevity of reptiles and amphibians in N. American collections as of 1 November, 1975. Class: Society for the Study of Amphibians and Reptiles, Miscellaneous Publications, Herpetological Circular 6:1-32. Reptilia

Order: Crocodyli a

Alligator

Family:

Alligators and caimans are reptiles closely related to the crocodiles and forming the family Alligatoridae

Alligat oridae

(sometimes regarded instead as the subfamily

Alligatorinae). Together with the Gharial (family Gavialidae) they make up the order Crocodylia. Alligators differ from crocodiles principally in having the head broader and shorter, and the snout more obtuse; in having the fourth, enlarged tooth of the under jaw received, not into an external notch, but into a pit formed for it within the upper one; in lacking a jagged fringe which appears on the hind legs and feet of the crocodile; and in having the toes of the Genera

155 Alligator Caiman Melanosuchus Paleosuchus

hind feet webbed not more than half way to the tips. In general, the more dangerous crocodilians to human beings tend to be crocodiles rather than alligators. Alligators proper occur in the fluvial deposits of the age of the Upper Chalk in Europe, where they did not die out until the Pliocene age. The true alligators are now restricted to two species, A. mississippiensis in the southern states of North America, which grows up to 4 m (12 ft). in length, and the small A. sinensis in the Yang-tse-kiang, China. Their name derives from the Spanish el lagarto, "the lizard"). In Central and South America alligators are represented by five species of the genus Caiman, which differs from the alligator by the absence of a bony septum between the nostrils, and the ventral armour is composed of overlapping bony scutes, each of which is formed of two parts united by a suture. Some authorities further divide this genus into three, splitting off the smooth-fronted caimans into a genus Paleosuchus and the Black Caiman into Melanosuchus. C. sclerops, the Spectacled Alligator, has the widest distribution, from southern Mexico to the northern half of Argentina, and grows to a bulky size. The largest, attaining an enormous bulk and a length of 20 ft., is the near-extinct Melanosuchus niger, the Jacare-assu, Large, or Black Caiman of the Amazon. While all wild animals should be treated with respect, the Black Caiman is the only member of the alligator family posing the same danger to humans as the larger species of the crocodile family. Some crocodiles can be found in salty water, but most alligators stay in fresh water.

Species •

ORDER o o

CROCODILIA Family Crocodylidae: crocodiles

Family Alligatoridae   

American Alligator, Alligator mississippiensis Chinese Alligator, Alligator sinensis Spectacled Caiman, Caiman crocodilus crocodilus

      

o

Rio Apaporis Caiman, C. c. apaporiensis Brown Caiman, C. c. fuscus

Broad-snouted, Caiman Caiman latirostris Yacare Caiman, Caiman yacare Black Caiman, Melanosuchus niger Cuvier's Dwarf Caiman, Paleosuchus palpebrosus

Smooth-fronted Caiman, Paleosuchus trigonatus Family Gavialidae: Gavial

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Cultural aspects In Native American and African American folklore, the alligator is revered, especially the teeth, which can be worn as a charm against witchcraft and poison. Often, it is the butt of practical jokes by tricksters like Brer Rabbit. An urban legend states that people buy baby alligators after visiting Florida or other places where they are native and flush them down the toilet once they get big. The story goes that full grown alligators exist in the sewers of cities like New York City. Small released alligators and caimans, though, are occasionally found in northern lakes. Alligator skin was once a hot commodity, and was farmed in some areas, as pictured in the panoramic image below. Alligator is sometimes eaten as an exotic meat.

South Beach Alligator Farm (larger version) (5mb uncompressed tif)

Pop culture references A top hit from 1956 was "See You Later Alligator", as sung by Bill Haley & His Comets

CAIMANS

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Southern Mexico & the remainder of the Central American countries through South America to the northeastern portion of Argentina. Chile is the only South American nation which caimans to not inhabit.

HABITAT: Estuaries, swamps, lakes, streams, rivers, floodplains, and the surrounding terrestrial environment

POPULATION: GLOBAL Varies according to species.

STATUS: IUCN Varies according to species.

CITES Varies according to species. Listed on CITES Appendix I & II.

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