killer whale

killer whale, orca, or grampus, a large, rapacious marine mammal, Orcinus orca, of the dolphin family. Male killer whales may reach a length of 30 ft (9 m) and females half that length. The killer whale is black above, with a sharply contrasting white oval patch around each eye; its belly is white with white markings projecting up along the animal's sides. It has a high, triangular dorsal fin midway between head and tail, and broad, paddle-shaped flippers. The killer whale is worldwide in distribution. It is a swift and ferocious animal, armed with more than four dozen sharp teeth, and is the only cetacean (see whale) that feeds regularly on birds or mammals. Killer whales eat seals, sea birds, and fish, and in packs they will even attack larger whales. Different groups, or ecotypes, of killer whales, however, specialize in different prey; these ecotypes do not appear to interbreed, and some scientists believe that there are in fact several species of killer whale. The female gives birth to a single calf, up to 7 ft (2.1 m) long, following a gestation period of approximately one year. Females mature in 6 to 7 years, males in 12. They are classified in the phylum Chordata, subphylum Vertebrata, class Mammalia, order Cetacea, family Delphinidae.