Science Fair Project Encyclopedia
O. rosmarus rosmarus
O. rosmarus divergens
Walruses are large semi-aquatic mammals that live in the cold Arctic seas of the Northern Hemisphere. Two subspecies exist: the Atlantic, Odobenus rosmarus rosmarus, and the Pacific, Odobenus rosmarus divergens. The Pacific walrus is slightly larger, the male weighing up to 4000 lb (1.8 t).
The English word walrus comes from the Dutch walrus, apparently a folk-etymology inversion from an Old Norse form resembling hrosshvalr, a kind of whale.
The walrus is a member of order Carnivora and is the only species in the family Odobenidae. The compound odobenus comes from odous (Greek for "tooth") and baino (Greek for "walk"), based on observations of walruses using their tusks to pull themselves out of the water. Rosmarus originates in the Swedish word for walrus. Divergens in Latin means "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 ft (91 m), sometimes staying under for as long as a half hour. Clams and mollusks form a large part of their diet. Male walruses compete for territory, often fighting each other; the winners in these fights breeds with large numbers of females. Older male walruses frequently bear large scars from these bloody but rarely fatal battles.
Pacific walruses spend the summer north of the Bering Strait in the Chukchi Sea along the north shore of eastern Siberia, around Wrangel Island, in the Beaufort Sea along the north shore of Alaska, and in the waters between those locations.
In the spring and fall they congregate 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 have a breeding season in mid-winter, 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 with each other aggressively for this display-space. Mating probably takes place in the water. After fertilization the fertilized egg remains dormant for several months, then a gestation period of 11 months follows. When a calf is born it is over 3 ft (1 m) long and able to swim. Birth takes place on the pack ice; the calf nurses for about 2 years, spending 3 to 5 years with its mother. Females mature at about 6 years, males at 9 or 10. A walrus lives about 40 years.
Walruses spend about half their time in the water and half their time on beaches or ice floes 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. The walrus's tusks serve to pry out shellfish from their beds.
About 200,000 Pacific walruses exist; Alaskan natives harvest about 3000 annually. They use their long tusks (elongated canines) for fighting and for display. Humans use ivory from the tusks for carving. The natives call the penis bone of male an oosik and use it in making knives. Walruses have only two natural enemies: humans 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.
Federal laws in both the USA and in Canada protect walruses and set quotas on the yearly harvest. Only under rare circumstances may non-native hunters gain permission to kill a walrus legally. The law prohibits the export of raw tusks from Alaska, but walrus-ivory products may come on the market if first sculpted into scrimshaw by a native craftsman. Commercial auction sites such as eBay make a large selection of "pre-ban" walrus ivory available.
About 15,000 Atlantic walruses exist: they live in the Canadian Arctic, in the waters of Greenland and in the waters of the western portion of the Russian Arctic. The Atlantic walrus once enjoyed a range that extended south to Cape Cod and occurred in large numbers in the Gulf of St. Lawrence.
The walrus in culture
In Western culture, fiction often depicts the species -- with its plump body and peacefully sleepy expression -- as a lovable and friendly animal, and its appearance may been interpreted as somewhat comical.
Walruses in literature
Farley Mowat's book Sea of Slaughter has a large section dedicated to the effects of hunting on eastern Canada's walrus population.
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