Physical characteristics

Walruses are large mammals. They are probably most noted for the extended size of their upper canines that protrude externally from the mouth as tusks. The tusks occur

A male Pacific walrus (Odobenus rosmarus) swimming and exhaling in Alaska. (Photo by © Keven Schafer/Peter Arnold, Inc. Reproduced by permission.)

Walrus calf rides on its mother's back. (Illustration by Michelle Menegh-ini)

Atlantic walrus (Odobenus rosmarus rosmarus) near the Arctic Ocean. (Photo by Dotte Larson. Bruce Coleman, Inc. Reproduced by permission.)

in both males and females, although those of males tend to be larger in diameter and shorter than those of females. The snout of the walrus distinguishes it from other seals in that it is flat or "pug nosed" and contains a pad of mustacial vib-rissae (whiskers) that are short and stout. These whiskers are used in detecting prey. There are no external pinnae,

Walrus calf rides on its mother's back. (Illustration by Michelle Menegh-ini)

Cross Section Through Walrus Skull

Cross Section Through Walrus Skull

Walrus mouth and snout anatomy allows for specialized finding and feeding on mollusks. (Illustration by Michelle Meneghini)
The walrus (Odobenus rosmarus) uses its tusks to aid in locomotion. (Photo by John Giustina. Bruce Coleman, Inc. Reproduced by permission.)

Walruses have a coat of hair covering most of their body, although some regions such as the neck and flippers are either sparse with hair or devoid of it completely. When dry, the hair is a light brown but it is darker in appearance when wet. Male walruses have large fibrous tubercles (bumps) around the neck region. The absence of these among females suggests a secondary sexual function for them.

The rotund appearance of walruses is a result of the thick layer of subcutaneous blubber. Adult females have a slightly thicker layer of blubber, being nearly twice as thick as males during the breeding period.

Like the otariids, walruses rotate the rear flippers under their body and lift themselves off the ground to walk on land. However, for swimming at sea, walruses are more like pho-cids in that they move their rear flippers from side to side to propel themselves. Unlike phocids, the fore flippers are used to steer and maneuver.

0 0

Post a comment