Arctocephalus Callorhinus †Eotaria Eumetopias Neophoca Otaria Phocarctos †Pithanotaria †Proterozetes †Thalassoleon Zalophus An eared seal, otariid, or otary is any member of the marine mammal family Otariidae, one of three groupings of pinnipeds.

Otariids arose in the Miocene (15–17 million years ago) in the North Pacific, diversifying rapidly into the Southern Hemisphere, where most species now live.

Traditionally, otariids had been subdivided into the fur seal (Arctocephalinae) and sea lion (Otariinae) subfamilies, with the major distinction between them being the presence of a thick underfur layer in the former.

Otariids have proportionately much larger foreflippers and pectoral muscles than phocids, and have the ability to turn their hind limbs forward and walk on all fours, making them far more maneuverable on land.

Sea lions are covered with coarse guard hairs, while fur seals have a thick underfur, which has historically made them the objects of commercial exploitation.

Mature male otariids weigh two to six times as much as females, with proportionately larger heads, necks, and chests, making them the most sexually dimorphic of all mammals.

Except for the Australian sea lion, which has an atypical 17.5 month breeding cycle, they form strictly annual aggregations on beaches or rocky substrates, often on islands.

Family Otariidae Although the two subfamilies of otariids, the Otariinae (sea lions) and Arctocephalinae (fur seals), are still widely used, recent molecular studies have demonstrated that they may be invalid.