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Previous Issues > July 2007 > Wildville! > Dolphins
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 Wildville!
Dolphins
Kingdom: Animalia
Phylum: Chordata
Class: Mammalia
Order: Cetacea
Suborder: Odontoceti
Family: Delphinidae
Dolphins are smaller members of the whale order Cetacea. Dolphins and their immediate kin are included in the scientific family Delphinidae. There are about 30 species in this family, which includes dolphins, pilot whales, killer whales and false killer whales. They are all toothed whales.
Sometimes people confuse dolphins and porpoises. They look similar, but dolphins have a pointed snout, and porpoises have a short, blunt snout. They are both mammals, not fishes. They are warm-blooded, which means they have a constant warm body temperature, no matter what the temperature is of their environment. Like other whales, dolphins have lungs and breathe through a single nostril. This blowhole is on top of their head.
Dolphins have two flippers or fins that serve as arms. They also have a triangular fin that sticks up on their back. Their horizontal tail is what propels them through the water. Most dolphins are seven to 10 feet long. Their skin is smooth and feels rubbery. Dolphins can jump up to 20 feet in the air and can swim at speeds up to 25 miles per hour.
Dolphins have very good hearing. You might wonder: Where are their ears? They have small holes on both sides of their heads, about three inches from their eyes. Sound waves in the water go through the dolphins skull to the inner ear region.
Bottlenose dolphins are found in warm water all over the world. They live in groups called pods. The size of the pod varies, but on the coast of Florida, the average is about seven animals. The pods usually include mothers and their calves. A calf stays with its mother three to six years, or even longer. Dolphins establish strong bonds with each other. Bottlenose dolphins hunt together. Certain animals become friends and prefer association with each other. They even recognize each other after being separated for a long time. But sometimes they arent so friendly with each other. The bottlenose dolphins establish dominance by biting, chasing, jaw-clapping and smacking their tails on the water. They also scratch each other with their teeth, leaving scars on their skin.
Sources: Brittanica Student Encyclopedia; Discovery Cove and SeaWorld, www.seaworld.org. Photo courtesy of Discovery Cove.
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