Atlantic Bottlenose Dolphin (Tursiops truncatus)

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HISTORY AND DESCRIPTION: The dolphin is a marine mammal. This means that it is warm-blooded, has some fur (whiskers really), gives live birth, makes milk for its babies, and lives in salt water. (Some other kinds of dolphins live in fresh water.) A dolphin is definitely not a fish. It is actually a small whale, and is in the same family as killer whales and pilot whales. Bottlenose dolphins are usually eight to nine feet long; (the males are bigger than the females). Their skin is a grayish color, with a lighter belly. When the air and water are very warm, their bellies may turn light pink. A dolphin’s skin feels rubbery, and they have a thick layer of blubber underneath to keep them warm. Blubber is heavy; dolphins weigh 400-500 pounds. Dolphins breathe air, and must come up to the surface of the water regularly. They only have one nostril, located on the top of their head. This is called a blowhole. (They use the blowhole to breathe, but they have no sense of smell!) A dolphin’s flippers actually have finger-like bones inside! Scientists believe that dolphins used to be land animals. 50-60 million years ago, these land animals started living in the water so they could catch fish easier. As they became better swimmers, they became more like dolphins, and less like land animals. Today, they still have finger bones because they used to have arms and legs on land! The dolphin’s tail fluke (fin) is not perpendicular (up and down) like a fish or a shark. Instead, the fluke spreads out side to side. When a dolphin swims, he pushes his tail fluke up and down to help him dive or leap out of the water. Dolphins may seem friendly, but they are still wild animals. Never swim up to a wild dolphin!

HABITAT, SENSES, FEEDING, COMMUNICATION: Dolphins like to live in warm, shallow waters along the coast. Sometimes they come into large rivers (like the St. Johns River in Jacksonville), and sometimes they go further out to sea. Dolphins live in family groups called pods. There are often about twelve dolphins in a pod, but sometimes several hundred dolphins get together. They don’t usually migrate, but they may follow schools of fish that are moving. Adult dolphins eat about 14 pounds of fish, shrimp, and squid each day. (They have about 100 pointy cone-shaped teeth to help them catch and eat their food.) The dolphins’ powerful tail fluke also helps them hunt; they can chase fish at 45 miles per hour. Dolphins see well enough, but their sense of hearing really helps them in the dark ocean. When dolphins are hunting, they make a lot of squeaks and clicks. People don’t notice many of these "ultrasounds" because human ears can’t hear them, but dolphins can. The ultrasounds travel through the water and bounce off of fish that are swimming nearby. This is called echolocation. The bounced-off sounds, or echoes, come back to the dolphin. When he hears them, he knows exactly where the food is and how to find dinner, even in the dark!

COMMUNICATION, REPRODUCTION, AND LEGAL STATUS: Will dolphins ever be able to talk to people? Good question. Right now, there is no evidence that dolphins have a language like us, but they definitely communicate. They tell each other about the location of food and dangerous animals, and they have a great sense of humor. The dolphin’s echo-system or SONAR, may be able to see inside other animals. So, the dolphin could tell if a shark’s stomach was empty and let the other dolphins know "hungry shark nearby - danger!" Or a Sea World dolphin could tell if his trainer was upset if her heart was beating really fast. Dolphins can perceive many things that people can’t. They may not have a true language, but they definitely communicate. Mothers and babies, in particular, have a very strong bond. (However, males and females do not stay together after they mate.) Baby dolphins are usually born around Florida between February and May. The mother feeds milk to her baby for up to 1 1/2 years, but the baby starts to eat fish when he’s about six months old. The mother won’t have another baby for 2-3 years. She spends this time teaching the first baby to survive. Even after she has a new baby, the older brother or sister will stay nearby until it is 4 or 5. Female dolphins grown up at 5-12 years old, but the males don’t grow up until they are 9-13 years old. Many dolphins in the wild live to be 25-years-old. Bottlenose dolphins are protected by the Marine Mammal Act which says that you can’t kill, feed, or bother any marine mammal (seals, whales, otters, etc.) This only holds true for the United States. Many other countries still hunt dolphins and whales for food and for medicines made from their oil.

Check out the dolphin coloring page by clicking on the Animal Pages Coloring box below!

RESOURCES:

Ballenger, Liz & Tracy Lindsley. "Tursiops truncatus." http://www.oit.itd.umi...Tursiops_truncatus.ftl. (27 Jan 1997).

Blackstock, Regina. "Dolphins and Man...Equals?" http://www.polaris.net/^rblacks/dolphins.html. (27 Jan 1997).

Compton’s News Media, Inc. "Dolphin." http:.//www.ucsc.edu/mb/creatures/dolphin-1.html. (27 Jan 1997).

Kkinowski, Margaret. "Brains, Behaviour, and Intelligence in Cetaceans," High North. "11 Essays on Whales and Man," 2nd ed. 26 Sept. 1994. http://www.highnorth.no/br-be-an.html. (27 Jan 1997).

LeBoeuf, Nicole. "The Bottlenose Dolphin." Texas Marine Mammal Stranding Network. http: //www.rtis.com/na...sn/mmgulf/tursiops.html. (27 Jan 1997).

Reinartz, Ulrich. "Tursiops - Homepage." http://www.snafu.de/^ulisses/tursiops.html. (27 Jan 97).

Provided by the E. Dale Joyner Nature Preserve at Pelotes Island

St. Johns River Power Park, Jacksonville Electric Authority, Florida Power & Light

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