Saturday, November 12, 2011

Life of Walrus


Life of Sea | Walrus (Odobenus rosmarus) | The walrus is a large marine mammal with a discontinuous circumpolar flippered distribution in the Arctic and sub-Arctic seas of the northern hemisphere. The walrus is the only living species in the family and Odobenus genus Odobenidae. It is divided into three subspecies: the Atlantic Walrus (O. rosmarus rosmarus), who lives in the Atlantic, the Pacific walrus (O. rosmarus diver gens), who lives in the Pacific, and O. rosmarus laptevi, who lives in the Laptev Sea. Walruses are famous for their tusks and are the only pinnipeds (true seals, sea lions and fur seals) they have. The tusks can grow to 1 m in length, and males tend to have larger tusks than females. The tusks are used for keeping airways open holes in the ice, to control and helping the walruses get himself out of the water on an ice floe.

Scientific classification
Kingdom:     Animalia
Phylum:     Chordata
Class:     Mammalia
Infraclass:     Eutheria
Order:     Carnivora
Suborder:     Caniformia
Superfamily:     Pinnipedia
Family:     Odobenidae
Allen, 1880
Genus:     Odobenus
Brisson, 1762
Species:     O. rosmarus

The Walrus' body shape shares characteristics with both sea lions and true seals. As with sea lion, could turn her rear flippers and go on all fours, but the swimming technique is more like that of true seals, rely less on flippers and more sinuous whole body movements. Even if true seals, lack external ears. The most striking feature of the walrus's long tusks. Tusks are slightly longer and thicker in men who use them for fighting, dominance and the screen of the strongest males with the largest tusks typically dominate social groups. Tusks are also used to form and maintain holes in the ice and help the walrus to climb out of the water on ice.

Previously assumed that tusks were used to dig out prey from the sea floor, but analysis of wear patterns on the tusks indicate that they are dragged through the sediment, while the top of the muzzle is used for digging. While the teeth of the walrus is highly variable, they generally have relatively few teeth other than fangs. Surrounding the tusks is a broad mat of stiff bristles ('mystacial vibrissae'), so the walrus a characteristic whiskered appearance.

Apart from the vibrissae, the walrus is sparsely covered with fur and appears bald. His skin is very wrinkled and thick, up to 10 cm (3.9 in) around the neck and shoulders of men. Young walruses are deep brown and grow paler and more cinnamon colored as they age. Old men, in particular, are almost pink. Because the skin blood vessels constrict in cold water, the walrus appears almost white while swimming. The Walrus has an air pocket under his throat that acts as a flotation bubble and allows you to bob vertically in the water and sleep. The males possess a large baculum (penis bone), the largest land mammal of all, both in absolute terms and relative to body size.

Walruses prefer shallow shelf regions, foraging mainly on the seabed, often sea ice platforms. They are not very deep divers compared to other pinnipeds. They can stay underwater as long as half hour. The walrus has a diverse and opportunistic diet, eating more than 60 genera of marine organisms, including shrimps, crabs, tube worms, soft corals, tunicates, sea cucumbers, various mollusks, and even other parts of its large size pinnipeds.Due and the tusks, the walrus has only two natural enemies: the orca and the polar bear. The walrus is not comprise a significant part of the diet of both predators are. Both the orca and the polar bear are also most likely to prey on walrus calves.

Walrus plays an important role in religion and folklore of many Arctic peoples. Skin and bones are used in some ceremonies and the animal often seems legends. Because of its striking appearance, large bulk and instantly recognizable whiskers and tusks, the walrus also appears in the popular culture of the peoples with little direct experience with the animal, especially in English literature.

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