Walrus in Bering Sea, Alaska, Photo courtesy of Office of NOAA Corps Operations.
Walruses are only found in the Northern Hemisphere. They inhabit both the Northern Atlantic and Pacific oceans, with the Pacific walrus being larger (3% longer and 10% heavier) than the Atlantic walrus. Pacific walruses also have longer tusks than Atlantic walruses, as can be seen in the photos above. The walrus on the left appears to be the Pacific subspecies since its tusks are significantly longer than the walrus on the right, most likely an Atlantic walrus. Walruses are also sexually dimorphic, with males growing much larger than the females. In this species the males are 20% longer and 50% heavier than females. Walruses are most noted for their large canine tusks. In fact, their scientific name means “tooth-walker” since walruses sometimes use their large tusks to help them move around. They have small heads that sit upon large bodies. Their skin is tough and males are covered by wart-like nodules or tubercles (fibrous, callous-like skin patches) that protect them from tusk attacks by other males. Compared to other pinnipeds that feed on fish and organisms in the water column, walruses have a unique feeding style – they feed on small organisms on the sea floor.The sounds produced by walruses are most often heard in association with mating. Males make underwater vocalizations that sound like taps, knock, pulses, and bell-like sounds. Walrus calls range in frequency from 100 Hz – 10 kHz. These sounds are typically followed by visual displays at the surface.
Walrus in icy Arctic waters. Courtesy of the Russian State Museum of Arctic and Antarctica.