Eared Seal - Anatomy and Appearance

Anatomy and Appearance

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. They are generally considered to be less adapted to an aquatic lifestyle, since they breed primarily on land and haul out more frequently than true seals. However, they can attain higher bursts of speed and greater maneuverability in the water. Their swimming power derives from the use of flippers more so than the sinuous whole-body movements typical of phocids and walruses.

Otariids are further distinguished by a more dog-like head, sharp, well-developed canines, and the aforementioned visible external pinnae. Their postcanine teeth are generally simple and conical in shape. The dental formula for eared seals is: . Sea lions are covered with coarse guard hairs, while fur seals have a thick underfur, which have historically made them the objects of commercial exploitation.

Male otariids range in size from the 70-kg (150-lb) Galápagos fur seal, smallest of all pinnipeds, to the over 1000-kg (2200-lb) Steller sea lion. Mature male otariids weigh two to six times more than females, with proportionately larger heads, necks, and chests, making them the most sexually dimorphic of all mammals.