Walrus

There are two sub-species of walrus: the Pacific walrus (Odobenus rosmarus divergens) and the Atlantic walrus (Odobenus rosmarus rosmarus). The Pacific walrus is larger than their Atlantic cousins.

Walrus migrate with the moving ice floes, but never venture far from the coast as they feed in shallow waters. They can swim to a depth of around 100 metres to feed on molluscs and other invertebrates, but on average do not go much deeper than 20-30 metres.

Walrus are recognisable by their long tusks, which can grow to more than one metre in length. Their skin is a dark brown and is covered by a thin layer of small coarse hairs.

The walrus is a pinniped, or fin-footed mammal, and is related to seals and sea lions.

Interesting fact
All male walruses, and a few female walruses, have a large air sac in their throat. Researchers believe that it is to help keep their head above the water when they swim. It is also used to make a bell-like sound during mating.

Distribution
The Pacific walrus is found around Alaska and north-east Russia and numbers around 200,000. The Atlantic walrus is found in the Canadian Arctic, in the waters of Greenland, Svalbard and the western portion of the Russian Arctic and numbers around 15,000.
 
Threats
Walrus need thick sea ice to support their weight and the shallow waters of the coastal zone to feed. As the warming climate in the Arctic reduces the thickness and expanse of the ice, it also reduces the walrus’ habitat.  

Science website
US Geological Survey: Walrus home

Education website
PBS: Toothwalkers: Giants of the Arctic Ice