Scientist recognize more than 70 species of whales. These two groups of whales differ from each other in several ways. Toothed whales are named for their simple, peglike teeth, which vary considerably in number and size among the species. The teeth of dolphins are conical and interlocking, while those of porpoises are spade-shaped. Teeth are adapted for grasping and tearing, rather than chewing.
Baleen whales have no teeth.
They have stiff, fringed plates of baleen that hang down from the upper jaw. Baleen is composed of keratin, a protein compound that also makes up human hair and fingernails. Baleen whales are filter feeders. They take in huge mouthfuls of water containing small fishes or invertebrates. The baleen traps the prey, and water is forced back out of the mouth.