The elephant seal and the Antarctic fur seal are the only Antarctic seals that do not range south of the Antarctic Peninsula. Phocids and Otariids differ in two easily recognizable ways. First, Phocids have no external ear, while the Otariids have ear flaps. Further, the Phocids have short front flippers and move awkwardly on land. Otariids have much larger front flippers that allow them to move adeptly on land, with their hind flippers tucked underneath their bodies.
Seals have special muscles to open and close their nostrils, important during diving.
They can also slow their metabolism and heart rate during dives to conserve energy and air, and their lungs and blood vessels are especially efficient in absorbing oxygen. Crabeater seals are found throughout Antarctica. The strong jaws and highly developed teeth of leopard seals allow them to feed on crabeater pups and penguins, in addition to krill. Their name comes from their spotted coat. Males are smaller.