Odobenidae: Walrus Family
The single species of walrus resembles the sea lions in that its hind flippers can be brought forward in order to help it move on land. However, it cannot move as fast or adeptly as sea lions, and will often just drag itself forward.
These massive members of the seal family are unmistakable. Their distinctive long tusks - actually modified canine teeth - are present in both sexes.
Walruses live among the ice floes of the Arctic Ocean. These huge sea mammals are well known for their long tusks, which they use to stab opponents during fights. Walruses also use their tusks to "haul out", or pull themselves on to floating ice, and sometimes hook themselves to floes so that they can sleep while still in the water.
Walruses use their whiskered snouts to root out prey and blast away sediment with jets of air squirted from the mouth. They tackle shelled prey by holding them in their lips and sucking out the soft bodies.
Walruses live in large herds, sometimes of many thousands. In winter they feed in areas of thin sea ice, avoiding thick, unbroken ice, which they cannot break through from beneath. In summer, when the ice recedes, they spend more time on land.
Walruses have long tusks growing out of the upper jaw. Males, which are twice the size of females, also have longer tusks. Their bodies are reddish-brown and sparsely covered in coarse hairs. Males have two air pouches inside the neck, which they use to amplify their mating calls.
Male walruses, called bulls, will battle ferociously with each other on land for mating rights during the breeding period. Mating takes place in the water, and calves are born on the ice 11 months later. The young stay with their mothers for three years.
They can inflict serious injuries with their tusks, with the largest individuals usually proving to be dominant. In the sea they can dive to depths of 75 m (250 ft) in search of food, relying on their whiskers to locate prey on the seabed. Walruses face few dangers, although they are at risk from killer whales. Polar bears represent a threat, too.
Distribution: Occurs in the Pacific, off Alaska and in the Chukchi Sea. Atlantic population extends from northern Canada to Greenland. Both populations move south in winter.
Habitat: Pack ice.
Weight: 555 - 889 kg (1250 - 2000 lb); males are heavier.
Length: 243 - 350 cm (96 - 138 in); up to 152 cm (60 in) tall.
Maturity: 6 - 7 years; males rarely mate before 15.
Gestation Period: 365 days; embryonic development starts 3 - 4 months after mating.
Breeding: 1; weaning occurs at 26 weeks.
Diet: Piscivorous, hunting shellfish, fish and octopus; occasionally kills seals and scavenges on whale carcasses.
Lifespan: 40 years.
Up to 15 cm (6 in) of fat can be present beneath the skin, protecting against the cold.
Up to 700 whiskers are arranged in 15 rows.
The flippers are smooth and free of hair on their upper surface.
The tusks can measure up to 90 cm (36 in) in males, but are shorter in females.
Gaining a hold
The front flippers act as initial anchorage, pulling the body up.
The walrus can then use its tusks to help haul it on to land.
Walruses often rest together in groups on ice floes.
Walruses need to be able to leave the sea and haul themselves on to land. Here they can actually move as fast as we can!