Sea lions are any of seven species in six genera of modern pinnipeds including one extinct (the Japanese sea lion). Sea lions are characterized by the presence of external ear pinnae or flaps, long front flippers, and the ability to walk on four flippers on land. Their range extends from the subarctic to tropical waters of the global ocean in both the northern and southern hemispheres with the notable exception of the Atlantic Ocean. They are generally found in shallow waters of coastal areas with abundant food resources.
Together with the fur seal, they comprise the Otariidae family, collectively known as eared seals. Until recently, sea lions were grouped under a single subfamily called Otariinae to distinguish them from the fur seals Arcocephalinae, based on the most prominent common feature between all species, namely the lack of dense underfur characteristic of the latter. Recent genetic evidence, however, strongly suggests that the Callorhinus, the genus of the Northern fur seal is more closely related to some sea lion species than to the fur seal genus Arctocephalus. Therefore the fur seal/sealion subfamily distinction has been largely eliminated. Nonetheless, all sea lions have certain features in common, in particular the coarse, short fur, greater bulk and larger prey than fur seals.
Some species of sea lions are readily trainable and are often a popular attraction at zoos and aquariums. The archetypal circus seal performing behaviors such as throwing and catching balls on its nose and clapping is almost always a sea lion.
The government of Japan has set a quota of 116 kills per year in Hokkaido, as sea lions are seen as a threat to commercial fisheries. International environmentalists and local fishery advocates continue to debate the issue.
Sea lion attacks on humans are rare, but have occurred in at least a single notable case, in which a 13 year-old Australian girl was attacked while in the water. Sources said that the likeliest explanation was that the animal was attempting to play with the girl.
A probable hybrid sea lion from a cross between the California sea lion (Zalophus californianus) and the South American sea lion (Otaria byronia) was reported in the a 2002 issue of the Journal of Mammology, according to the French National Center for Scientific Research.