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Friday 17 December 2010

Tusked Sea Monster

There is only one species of walrus (Odobenus rosmarus), however it is separated into two subspecies – the Atlantic walrus and the Pacific walrus. The Pacific animal tends to be the larger and has nostrils placed higher on the muzzle. Otherwise the physique and habits of the two are just about identical.

With very wrinkly and thick skin, walruses are distinguished by their long white tusks, broad head, small eyes, grizzly whiskers, short muzzle, flat flipper, and bodies full of blubber (body fat). A male walrus can weigh as much as two tons and the female is usually over one ton. Both sexes have prominent tusks, but the females are less massive than the male´s. Their tusks, which are, in fact, highly developed canine teeth, grow continually throughout a walrus´s life – they measure about three feet (one meter) in length in mature bulls. The tusks are in constant use for such purposes as hauling their enormous bodies out of frigid waters, ploughing the seabed for shellfish, to crack breathing holes in the ice from below during the winter and fighting.

The Walrus´s diet includes clams, mussels, snails, shrimp and other bottom dwelling invertebrates that they locate through their extremely sensitive whiskers which act like detection devices. A walrus can eat up to 4.000 clams on one feeding! (no wonder they are so gigantic…) They are also known to eat seals or even the young of their own species when food is scares. A few old males are said to take this carnivorous diet and to be distinguishable by stained tusks and greasy skins.

The walrus´s blubbery bodies allow them to live with comfort in the Arctic region – this insulation enables the walrus to remain indifferent to cold in winter. Nor does dissipation of heat in summer present any problem; in hot weather a basking walrus turns a rich rose color as blood vessels in its skin dilate to dispel body heat. Walruses have air sacs in their throat which allow them to sleep with their head held up in the water. Nursing females use this standing position as they nurse.

A fully grown walrus is magnificently adapted to its life on the ice and in the sea. It is a strong swimmer with enormously developed hind flippers which measure almost 3 feet across. Their size and mighty tusks mean that walruses have few predators, though one may occasionally fall victim to a hungry killer whale (or orca) and the polar bear. Walrus numbers were very reduced by commercial hunters until 1972 when the Marine Mammal Act started protecting them. Now only native people in the Arctic are currently allowed to hunt them and the populations have grown in size. Native peoples in the Arctic hunt the walrus for food and put every part of its body to good use.

Image: WIKIMEDIA COMMONS

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