cetacean(redirected from cetaceous)
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whaleany aquatic EUTHERIAN mammal of the order Cetacea, comprising the porpoises, dolphins and whales.
Cetaceans are completely aquatic, have lost their hind limbs during evolution and have fin-like forelimbs, often a dorsal fin and, in marked comparison with fishes, a blowhole and transverse tail fin. The young are large at birth and suckled like other mammals. Cetaceans possess an extensive outer layer of fat associated with their marine habit, have a large brain and are capable of complex communication.