- Common Name
- cetaceans, whales, dolphins, porpoises
- Cetacea (suborder Odontoceti: toothed whales; suborder Mysticeti: baleen whale)
- 10 families
- Genus Species
- 40 genera; at least 80 species
- Visually, the two suborders can be easily distinguished by the presence of teeth and a single blowhole (Odontocetes), or baleen and two blowholes (Mysticetes).
- In general, baleen whales are much larger than toothed whales, ranging in length from about 6.4 to 27 m (21 to 85 ft.). Most toothed whales are less than 6.1 m (20 ft.) long.
- Sexual Maturity
- Life Span
- Toothed whales are named for their simple, peg-like 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. River dolphins have numerous teeth; most beaked whales have only one or two visible pairs. 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.
- Toothed whales include dolphins, porpoises, belugas, narwhals, sperm whales, river dolphins, and beaked whales. Baleen whales are represented by 11 species, including the right whale, gray whale, blue whale, and humpback whale.
- To learn more about whales, including toothed whales, explore the Baleen Whales Infobook, Beluga Whales Infobook, Bottlenose Dolphin Infobook, Commerson's Dolphin Infobook, and Killer Whales Infobook.
Ecology and Conservation
Many populations of whales have faced severe declines in numbers due to mortality from whaling, entanglement in fishing gear or loss of habitat. Various international and national laws protect cetaceans.
Jefferson, T.J. Leatherwood, S. and M.A. Webber. FAO Species identification Guide. Marine Mammals of the World. Rome. FAO, 1993.
Leatherwood, Stephen, and Reeves, Randall R. The Sierra Club Handbook of Whales and Dolphins. San Francisco: Sierra Club Books, 1983.
Reeves, R. R., Stewart, B.S., Clapman, P.J., and J.A. Powell (Peter Folkens illustrator). National Audubon Society: Guide to Marine Mammals of the World. New York: Random House, 2002.