Walrus

Walrus
Scientific classification
Kingdom: Animalia Phylum: Chordata Class: Mammalia Order: Carnivora Family: Odobenidae Genus: Odobenus Species: rosmarus
Binomial name
Odobenus rosmarus

Walruses are large semi-aquatic mammals that live in the cold Arctic seas of the Northern Hemisphere. The two subspecies are the Atlantic, Odobenus rosmarus rosmarus, and the Pacific, Odobenus rosmarus divergens. The Pacific Walrus is slightly larger, the male weighing up to 4000 pounds.

Odobenus is compounded from "odous" Greek for tooth and "baino" Greek for walk, based on observations of walruses using their tusks to drag themselves along. Rosmarus is based on the Swedish word for walrus. Divergens is based on Latin for turning apart, referring to the tusks.

Walruses mate in the water and give birth on land or ice floes. They feed in the water, diving to depths of 300 feet, sometimes staying under for as long as a half hour. Male Walruses compete for territory, often fighting each other; the winners in these fights breed with large numbers of females.

Pacific Walruses spend the summer north of the Bering Strait in the Chulchi Sea along the north shore of eastern Siberia, around Wrangle Island[?], in the Beaufort Sea along the north shore of Alaska, and in the waters between those locations.

Smaller numbers of males summer in the Gulf of Anadyr on the south shore of the Chulchi Peninsula of Siberia and in Bristol Bay off the south shore of southern Alaska west of the Kenai Peninsula.

In the spring and fall they congegate in the Bering Strait, adjacent to the west shores of Alaska, and in the Gulf of Anadyr. They winter to the south in the Bering Sea along the eastern shore of Siberia south to the northern part of the Kamchatka Peninsula, and along the southern shore of Alaska.

Walruses spend about half the time in the water, half the time hauled out on a beach or ice flow where they gather in large herds. They may spend several days at a stretch either on land or in the sea. In the sea they sometimes catch fish but generally graze along the sea bottom for clams which they suck from their shells.

There are about 200,000 Pacific Walruses; about 3000 are harvested annually by Alaskan natives. They have long tusks, which are elongated canines and which are used for fighting and display. Ivory from the tusks is used for carving. The only natural enemies of of the walrus are man and the Polar Bear. Polar Bears hunt walruses by rushing at them, trying to get the herd to flee, then picking off calves or other stragglers.

The breeding season for walrus is midwinter, a time spent in the southern Bering sea. The males show off in the water for the females who view them from pack ice. Males compete aggressively for this display space with each other. Mating is probably in the water. After fertilization the fertilized egg is dormant for several months, then a gestation period of 11 months follows. When a calf is born it is over 3 feet long and able to swim. Birth takes place on pack ice; the calf nurses for about 2 years, spending 3 to 5 years with its mother. Females are mature at about 6 years, males at 9 or 10. A walrus lives about 40 years.

There are about 15,000 Atlantic Walrus which live in the Canadian Arctic, the waters of Greenland, and the waters of the western portion of the Russian Arctic. The Atlantic walrus once enjoyed a range that extended south to Cape Cod and were found in large numbers in the Gulf of St. Lawrence.

The Walrus is a member of order Carnivora and is the only species in the family Odobenidae.

External Links

• USGS - Pacific Walrus Research (http://www.absc.usgs.gov/research/walrus/home)