Page 154 - Present Day Wildlife_Float

The walrus (Odobenus rosmarus) is a large carnivorous marine mammal and is the only extant
species in the genus Odobenus in the, pinniped, family Odobenidae. The walrus is split into two subspe-
cies: the Atlantic walrus (Odobenus rosmarus rosmarus) which resides in the northern waters of
Canada, Greenland, Norway and Russia, and the Pacific walrus (O. rosmarus divergens) which is
found across a wide range between Russia and Alaska USA, in the Chukchi and Bering seas. The size of
the walrus is divided between the two subspecies with the largest being the Pacific walrus which grows
to a length of about 3.6 metres and a weight of around
1,700 kg, while the Atlantic walrus are smaller at about 2
to 2.4 metres long and weigh around 910kg. The Atlantic
walrus also has shorter tusks and its large snout is flatter
and more rounded than the Pacific walrus. It’s also nu-
merically the lesser of the two with a population of only a
quarter of the entire walrus population, and is therefore
more sparsely populated in the areas it inhabits.

The walrus has a very distinctive look. It has very
thick and extremely wrinkled greyish skin with a light cov-
ering of fur. In males the skin can be up to 10 cm thick
around the neck and shoulders. Beneath its skin it has a 15
cm thick layer of insulating blubber, protecting it from the
extremely cold artic conditions. It has a rounded head,
small eyes, and no external ears. It has a large but blunt
snout, with two overgrown upper canine teeth forming
long pointed tusks surrounded by a mat of stiff sensitive
bristles. It uses its tusk to haul itself out of the water or
keep breathing holes open in the ice, for defence or fighting with other walruses. It
has four large flippers, and with the rear pair able to turn forwards, it can walk on
land. It also has an air sac under its throat that keeps its head above water allowing it
to sleep while bobbing about in the water.

The walrus’s lifestyle is divided between the sea and the land. They spend a lot of
time in shallow waters hunting for food. They are not deep divers and prefer, for safe-
ty, to hunt from offshore sea ice, coming on land, usually in great numbers, to social-
ise and rest. On land the walruses are easily startled. Any hint of danger or loud noise,
will send them into a stampede to get back into the safety of the water. Those too
young or too slow are simply crushed in the throng of stampeding animals and litter
the beach, either dead or dying, once the stampede has passed.

Walruses mate in deep water. In the winter mating season, large groups of males
will congregate, with prospective males making pulses or tapping sounds to attract a female. They will
also fight for dominance, and using their tusks as weapons will often inflict permanent scars on each
other. Females mate with only one male and once mating is over the male will usually return to the shal-
low coastal waters, leaving the female on the sea ice to give birth and look after her young. As summer
arrives the walruses migrate into fertile southern waters with massive numbers of Pacific walruses pour-
ing through the Bering Straits toward the coasts of eastern Russia and southern Alaska. It’s during the
summer that large numbers of smaller groups are often seen searching out known fertile feeding areas,
possibly to regain that essential fat needed to help sustain them when they return to the north in the
winter months.

The walrus is a carnivore and is known to feed regularly on, shrimp, crabs, spoon worms, tube
worms, soft corals and tunicates. However, how the walrus hunts on the sea floor and what constitutes
its complete diet is still a bit controversial. For instance, researchers have found seal and bird remains
in the guts of a few Pacific walrus. These are thought to be one off findings, as does occur from time to
time with opportunistic feeders. However, some disagree. Also, some believe the walrus uses their tusks
to dig for food. There is no evidence or marks on the tusk to support this, but there is evidence of it us-
ing its tusks to brush the sea bed. This would be in line with what is already known; that it uses it highly
sensitive whiskers to feel-out food on the sea bed. With its hunting usually out of sight on the sea floor
and dispersed across such a huge area the chances are this controversy will continue for some time.
Apart from man, an adult walrus has few, if any, natural predators. The orca and polar bear do prey on
walrus but tend to hunt the young, as the adults with their long tusks are just too dangerous. (See:
Seals)