Cetacea

The order Cetacea includes whales, dolphins and porpoises.

Cetus is Latin and is used in biological names to mean "whale"; its original meaning was more general, "large sea animal". It comes from Greek ketos, a sea monster.

Cetaceans are the mammals most fully adapted to aquatic life. Their body is fusiform (spindle-shaped). The forelimbs are modified into flippers. The hindlimbs are vestigial, they do not attach to the backbone and are not exteriorly visible. The tail has horizontal flukes.

Cetaceans are nearly hairless, and are insulated by a thick layer of blubber.

Cetacea contains 10 families, 78 species.

• Suborder Odonticeti[?] (toothed whales)
  • Family Delphinidae[?] (bottlenose dolphin[?], killer whale)
  • Family Monodontidae[?] (narwhal, beluga)
  • Family Phocoenidae[?] (porpoise)
  • Family Platanistidae[?] (river dolphin)
  • Family Physteridae[?] (Sperm Whale[?])
  • Family Ziphidae[?] (beaked whale)
• Suborer Mysticeti (baleen whales)
  • Family Balaenidae[?] (Right Whale[?], Bowhead Whale[?])
  • Family Balaenopteridae[?] (Blue Whale, Humpback Whale)
  • Family Eschrichtiidae (Gray Whale)
  • Family Neobalaenidae[?] (Pygmy Right Whale)

External links

• American Cetacean Society (http://www.acsonline.org/)
• British Cetacean Site (http://www.crru.org.uk/) especially interesting is taxonomy (http://www.crru.org.uk/education/factfiles/taxonomy.htm)
• cetacea site (http://www.cetacea.org/)