They are more mobile on land than true seals, and are often seen in circuses and oceanaria. Their swimming power comes from their large front flippers. In California, this family includes California sea lions, Steller sea lions, northern fur seals, and Guadalupe fur seals. Their swimming power comes from their large, almost fan-like rear flippers. In California, this family includes harbor seals and northern elephant seals.
Walruses are distinctive for their two long tusks.
Walruses inhabit the Arctic seas and ice floes. They have no external ears, but can rotate their hind flippers and walk on land. They are set apart from other pinnipeds not only by their tusks, but also by the presence of two large air pouches, or sacs, extending from each side the pharynx. These pouches can be inflated to hold the head above water when sleeping, or used as resonance chambers to enhance underwater sound. Sea otters are the only marine representative of the mustelid family, which includes such land mammals as weasels and skunks.