[Illustration: FIG. 7.--Skull and dentition of Australian Sea-Bear (_Otaria forsteri_).]
The third and last family of the Pinnipedia, and thus of existing Carnivora, is the _Otariidae_, which includes the eared seals, or sea-lions and sea-bears. In all these animals, when on land, the hind-feet are turned forwards under the body, and aid in supporting and moving the trunk as in ordinary quadrupeds. There are small external ears. Testes suspended in a distinct external scrotum. Skull with post-orbital processes and alisphenoid canal. Soles of feet naked. By many naturalists these seals are arranged in a number of generic groups, but as the differences between them are not very great, they may all be included in the typical genus _Otaria_. The dental formula is i. 3/2, c. 1/1, p. 4/4, m. (1 or 2)/1; total 34 or 36. The first and second upper incisors are small, with the summits of their crowns divided by deep transverse grooves into an anterior and a posterior cusp of nearly equal height; the third large and canine-like. Canines large, conical, pointed, recurved. Molars and premolars usually 5/5, of which the second, third and fourth are preceded by milk-teeth shed a few days after birth; sometimes (as in fig. 7) a sixth upper molar (occasionally developed on one side and not the other); all with similar characters, generally single-rooted; crown moderate, compressed, pointed, with a single principal cusp, and sometimes a cingulum, and more or less developed anterior and posterior accessory cusps. Vertebrae: C. 7, D. 15, L. 5, S. 4, Ca. 9-10. Head rounded. Eyes large; ears small, narrow and pointed. Neck long. Skin of the feet extended far beyond the nails and ends of the digits, with a deeply-lobed margin. The nails small and often quite rudimentary, especially those of the first and fifth toes of both feet; the best-developed and most constant being the three middle claws of the hind-foot, which are elongated, compressed and curved.
Sea-bears and sea-lions are widely distributed, especially in the temperate regions of both hemispheres, though absent from the coasts of the North Atlantic. They spend more of their time on shore, and range inland to greater distances than the true seals, especially at the breeding-time, though they are obliged to return to the water to seek their food. They are gregarious and polygamous, and the males usually much larger than the females. Some possess, in addition to the stiff, close, hairy covering common to the group, a fine, dense, woolly under-fur. The skins of these, when dressed and deprived of the longer harsh outer hairs, constitute the "sealskin" of commerce. The species include _O. stelleri_, the northern sea-lion, the largest of the genus, from the North Pacific, about 10 ft. in length; _O. jubata_, the southern sea-lion, from the Falkland Islands and Patagonia; _O. californiana_, from California; _O. ursina_, the sea-bear or fur-seal of the North Pacific, the skins of which are imported in immense numbers from the Pribiloff Islands; _O. antarctica_ or _pusilla_, from the Cape of Good Hope; and _O. forsteri_, from Australia and various islands in the southern hemisphere. (See SEAL-FISHERIES.)