Dolphins

Facts about Dolphins •

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Dolphins are mammals; this means that they nurse their babies with milk from the mothers. Dolphins can swim up to 260 m. below the surface of the ocean. Dolphins can stay up to 15 minutes under water, but they cannot breath under the water. Dolphins use a technique called echolocation to find food and navigate. Dolphins live in groups formed by 10 to 12 individuals. There are 36 different kinds of ocean dolphins and 5 species of river dolphins. The largest dolphin is the “killer whale” (also known as Orca). The most known dolphin is the “ bottlenose dolphin”. Dolphins are warm-blooded. Dolphins communicate through sounds and whistles.

What do Dolphins Eat ? The food that dolphins eat is different for each species. While some dolphins eat fishes like herring, cod or mackerel, some others eat squids. Even more, large dolphins like the killer whales, eat some other marine mammals like seals or sea lions and sometime even turtles. Usually, the amount of fish that they eat depends on the kind of fish that they hunt. While mackerel or herring have a lot of fat, squid have not much fat, therefore, to get the energy required for their activities, dolphins have to eat more squid than mackerel. On average, a dolphin with a weigh of 200 Kg. to 250 Kg will eat between 10 Kg to 25 Kg of fish every day. Usually to hunt fish, some species of dolphins use a method called herding which is performed by a pod of dolphins where some of them surround a school of fish to compress them as much as possible, while some others take turns to dive through the compacted school of fish and feed.

Other usual method is corralling where fish is chased to shallow waters where they cannot escape. Some species catch larger fish by hitting them with their tails to stun them. Therefore the question about what do dolphins eat, has to be answered for every species in particular. In this video you can watch a pod of dolphins working together to feed themselves and using the technique called herding to catch the fish as they surround the school of fish and then some of them take turns to eat. In the video you can even watch fish jumping out of the water trying to scape and then they are catched as they jump.

How do Dolphins Communicate? Dolphins communicate through sounds and whistles. There are several kinds of whistles which are used by dolphins. Some species of dolphins can send the identity information through a signature whistles. Whistles also coordinate the group hunting which make feeding much easier for dolphins than doing it alone. Burst pulsed sounds are also made by dolphins with the purpose of communication, although there is not enough knowledge about dolphin communication.

Dolphin Echolocation Echolocation is a technique used by some animals to detect other animals, food and obstacles. As implied by its name, this technique uses the echo, produced by a sound emitted by the animals with this capability, to locate such objects.

Dolphins and some whales, besides some other animals, like bats, have this ability. The sound travels in the form of waves and when it is bounced back by solid objects either in water or air, it is then detected by the dolphin. This bouncing is called “echo” and it is the same as the voice echo we hear in caves, but at a much precise level. Animals with echolocation ability, are capable to detect this echo when is deflected back by a solid object. In the case of dolphins, they emit a a beam of clicking sounds forward in the direction of their head and receive the echo from this sounds in the lower jaw. This sophisticated system can calculate the distance where an object is located because of the time taken by the echo to return to the dolphin. As sounds can travel quite a distance in the water, dolphins are capable to detect dangers or food which is even out of sight. This technique is used by humans in radars or sonars where some kind of wave is emitted and the bounced back wave is detected and processed.

Bottlenose Dolphin Facts

The most popular dolphin is the Bottlenose Dolphin as it is the one we have seen in tv series, movies, and aquatic shows .

1. Bottlenose Dolphins can swim up to 260 m. below the surface of the ocean. However they need quick access to air in the surface, therefore bottlenose dolphins usually are shallow divers and close to the surface. 2. Bottlenose Dolphins can stay up to 15 minutes under water. However bottlenose dolphins usually stay only a few minutes diving.

3. Bottlenose Dolphins are social beings.

Bottlenose dolphins cooperate among each to get

food. To do this, they work in teams to optimize the effort of hunting. They also cooperate for calf rising, when usually one dolphin helps the mother to take care of the calves, very much like a midwife. 4. The bottlenose dolphin can grow up to 2.8 meters. While there are some other smaller species, there are some species much bigger like the killer whale. 5. Bottlenose Dolphins are warm-blooded. Their internal temperature is around 36 degrees. To keep this temperature they are surrounded by a thick layer of fat called “blubber” just below the skin. This fat, allow dolphins to resist cold temperatures and regulate their body temperature. 6. The average botllenose dolphin brain weighs 1500-1600 grams. If this is compared with the average human brain which weighs between 1200-1300 grs. bottlenose dolphin brain is larger, however this is not a conclusive evidence of dolphin intelligence as many other factors might be the cause of intelligence according to scientists, however this brain capacity

is a clear indication that dolphins have at least the potential of higher intelligence. 7. Bottlenose Dolphins are great communicators. They can make a unique signature whistle that may help individual dolphins recognize each other or perform any other kind of communication still unknown. Dolphins even make noises so loud that can stunt fish. 8. Bottlenose dolphins can swim 5 to 12 kilometers per hour. Although they can reach up to 32 km/h.