sea lion, fin-footed marine mammal of the eared seal family (Otariidae). Like the other member of this family, the fur seal, the sea lion is distinguished from the true seal by its external ears, long, flexible neck, supple forelimbs, and hind flippers that can be turned forward for walking on land. It differs from the fur seal in having a thin coat of short, coarse hair rather than soft, thick fur. Sea lions swim by rowing movements of the forelimbs, with the hindlimbs stretched out behind the body as a rudder. They feed primarily on fish and squid and are known to dive as deep as 600 ft (180 m) for food. They are found in the oceans of the Southern Hemisphere and in the N Pacific Ocean. When not breeding they inhabit waters close to shore, sometimes coming ashore to rest on rocky beaches and islands. Occasionally they ascend rivers. Their seasonal movements vary from one population to another and are not entirely known; they do not, however, undertake migrations comparable in length to those of the fur seal. During the breeding season they gather in colonies on the shore; the males establish territories and assemble harems, usually numbering 10 to 15 females. Females are considerably smaller than males, usually weighing about half as much. The small, dark brown California sea lion, Zalophus californianus, the so-called performing seal of circuses, is playful even in its natural environment. It is found on the Pacific coast of North America from Washington to S Mexico, on the Galapagos Islands, and in the Sea of Japan. Males may reach a length of 8 ft (2.4 m) and weigh up to 500 lb (225 kg). The northern, or Stellar's, sea lion, Eumetopias jubatus, is one of the largest of the pinnipeds, exceeded in size only by the elephant seal and the walrus. Males may grow up to 13 ft (4.9 m) long and weigh as much as 1,800 lb (820 kg); their fur is tawny brown. This species is found around the Bering Sea, on the Aleutian Islands, and down the Asian coast to N Japan and the American coast to S California. The South American sea lion, Otaria byronia, is found on the Pacific coast and S Atlantic coast of South America, and the Falkland Islands. The Australian sea lion, Neophoca cinerea, is found off S Australia; Hooker's sea lion, Phocarctos hookeri, lives on subantarctic islands of New Zealand. Sea lions have been hunted for blubber and hide and have also been killed in large numbers because fishermen blamed them for robbing their nets. There is now very little hunting of sea lions and the northern sea lion is under government protection. Sea lions are classified in the phylum Chordata, subphylum Vertebrata, class Mammalia, order Carnivora, suborder Pinnipedia, family Otariidae.