Walrus This order of aquatic mammals occurs along ice fronts and coastlines, mainly in polar and temperate parts of the oceans and adjoining seas of the world but also in some tropical areas and in certain inland bodies of water. There still is a question, however, whether this group warrants ordinal rank or would best be placed within the Carnivora. Pinnipeds are measured in a straight line from the tip of the nose to the tip of the tail. Adults weigh from about 35 kg to 3,700 kg, with Phoca containing some of the smallest species and Mirounga the largest.
Pinnipeds have a streamlined, torpedo-shaped body, with all four limbs modified into flippers.
The arm and leg bones are similar to those in the Carnivora, but the bases of the limbs, to or beyond the elbows and the knees, are deeply enclosed within the body. Each limb has five broadly webbed, oarlike digits, which form the flipper. In most species the head is flattened, and the face shortened, to aid in rapid propulsion through the water. The eyes, which are set in deep protective cushions of fat, are also adapted for underwater use. The cornea is flattened, and the pupil is capable of great enlargement to enable better sight in dark water.