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Dolphin Information

A Collection of Articles About Dolphins

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The bottlenose dolphin is probably the most familiar dolphin - but did you know that there are more than 30 dolphin species? Learn more about dolphins by clicking through the articles below.

What Is a Dolphin?

A dolphin is one of 36 species of toothed whales, also called odontocetes. Dolphins range in size from 5 feet (such as the spinner dolphin) to 30 feet (orca). Here you can learn more about the characteristics of dolphins.

Family Delphinidae

Dolphins are all in the Family Delphinidae, which contains 36 species. Animals in this family have streamlined bodies and cone-shaped teeth, an important distinction that sets them apart from porpoises, who have flat or spade-shaped teeth.

Types of Toothed Whales

Dolphins are toothed whales - a group of cetaceans that contains 72 species, about half of which are dolphins. View a list of dolphins and other toothed whales profiled on this site, along with images.

What Is the Difference Between a Dolphin and a Porpoise?

While the two words are often used interchangeably, there are differences between dolphins and porpoises. Although it's hard to see, especially in the wild, a major difference is in their teeth. Dolphins have cone-shaped teeth, while porpoises have spade-shaped or flat teeth. And some larger cetaceans, like baleen whales, don't have teeth at all.

Albinism in Whales and Dolphins

White Killer Whale Seen By NOAA Researchers in March 2008. H. Fearnbach, NMML, NMFS permit 782-1719
H. Fearnbach, NMML, NMFS permit 782-1719
Have you ever seen an albino whale or dolphin? A pink bottlenose dolphin, aptly named "pinky," was a hot news item after it was spotted in Calcasieu Lake, an inland saltwater estuary in Louisiana. The light-skinned, red-eyed youngster was originally spotted in 2007. Albinism has been documented in 20 cetacean species, including humpback whales, sperm whales, orcas, pilot whales, and bottlenose dolphins. Learn more about what causes this condition.

Why does a captive killer whale's dorsal fin collapse?

Have you noticed that orcas in captivity often have a dorsal fin that has fallen over? Why does this happen? Dorsal fins are made of cartilage. A wild orca swims so much that there is nearly constant pressure on each side of the dorsal fin. A captive orca spends more time at the surface, and may have to swim in a circle. Consequently, the tissue in the dorsal fin may atrophy (waste away) and fall over. This may happen to the whale's tail flukes, also.

How Do Dolphins Sleep?

In a 2012 study, a dolphin performed tasks accurately for 15 days. How can dolphins stay awake this long? Dolphins don't sleep the way we do - they engage in unihemispheric sleeping, which means that half of their brain rests, while the other half stays awake. This enables dolphins to move continuously and stay in touch with pod-mates if needed.

Dolphins: Second-Smartest?

Hope the Dolphin Image / Jennifer Kennedy, About.com
© Jennifer Kennedy, Licensed to About.com
If you use relative brain size to determine intelligence, then dolphins are second in intelligence only to humans. What does this mean?

Bottlenose Dolphin Image Gallery

Love dolphins? Check out this image gallery of bottlenose dolphins, which includes lots of fascinating facts.

Winter, the Bottlenose Dolphin

Winter, a dolphin who lost her tail when she was 3 months old, is arguably the most famous dolphin since Flipper. Winter's rehabilitation program led to the creation of a prosthetic tail, and the movie Dolphin Tale, which premiered in 2011. Winter lives at the Clearwater Aquarium in Clearwater, Florida, where visitors can see Winter, other bottlenose dolphins, and a number of other animals, including sharks, sea turtles, rays and otters.

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