Three subspecies of the walrus (Odobenus rosmarus) live in the cold water oceans in and around the Arctic Ocean.
- Atlantic Walrus Odobenus rosmarus rosmarus
- Pacific Walrus O. r. divergens
- Laptev Walrus O. r. laptevi
According to the 1839 text, The natural history of the amphibious carnivora
"It has been well remarked, that the Walrus forms a connecting link between the Mammalia of the land and those of the water, corresponding in some of its characters both with the Bullock and the Whale. It is often seen of the size of a great Ox, and sometimes exceeds the dimensions of the gigantic Elephant."
The most remarkable feature, however, in its countenance is its great muzzle, produced by the bony structure being accommodated for the reception of the tusks; these project from eighteen inches to two feet, and diverge at their points. The lips are remarkably thick, and are covered with great pellucid bristles as big as a straw. The neck is short; the body, very bulky, is broadest round the chest, and diminishes toward the tail, which is very short.
As a defence against the extreme cold, these animals have a hide that is from an inch to two inches thick, covered with close hair; and they likewise possess, like the Whale tribe, a coating of oily fat, with which their bodies are completely enveloped."
The walrus's great size and tusks have long served as a source of food and trophy for both native Eskimo and non-native hunters.
Pacific Walrus males, the largest walrus, can grow twelve feet long and weigh up to eight hundred pounds. Their tusks can grow over three feet in length.
From the seventeenth century to the mid-twentieth century, walrus hunting, along with whale hunting, occupied a substantial portion of most large-scale western commercial fleets.
Today the Atlantic population remains at low levels, and concerns are voiced that melting Arctic Sea Ice, the traditional Walrus breeding ground, could place stress on an otherwise recovered Pacific population.
Contemporary walrus hunting is limited to native Americans. Other states also regulate walrus hunting, and trade in walrus is further regulated by the Convention on International Trade in Endangered Species (CITES).
The Center for Biological Diversity (CBD) petitioned the United States government to List the Pacific Walrus (Odobenus Rosmaurs Divergens) as a threatened or endangered species under the Endangered Species Act.
The petition claims that the potential for increased sea ice melt in the Walrus's Arctic habitat (the Bering and Chuckchi seas) poses a threat to their existence, much the same as the threat facing the Polar Bear.
The basis for their claim is stated as follows:
"The effect of global warming will worsen in this century. Of importance for the Pacific walrus, the best available science indicates the near-complete disappearance of Arctic summer sea ice, including the ice of the Chukchi Sea, by 2030... or even as early as 2012... Winter sea ice in the Bering Sea is predicted to decline by 40% by mid-century... Without sea ice, the Pacific walrus will be forced into a shore-based existence for which it is not adapted, and without question would qualify as an endangered species."
The petition also points out the fact that sea ice loss represents the third in a series of human related threats to Walrus population levels. The first two threats came from large scale walrus hunting of the 19th and early 20th centuries that led to severe population declines. While current population levels are at, or near, their historic highs, the abrupt loss of sea ice habitat raises the possibility of an equally abrupt population decline.
The 2008 Red List assessment by the International Union for Conservation of Nature and Natural Resources (IUCN) reports, "Climate change is expected to have negative consequences for Walruses, and particularly severe consequences for the Pacific subspecies."
The scientific name for Odobenus rosmarus means tooth-walking sea-horse, referring to tusks present on both males and females. The tusks serve a variety of purposes such as helping them navigate on ice and land. Males also use their tusks for territorial defense.
They are large marine mammals, with males reaching close to twelve feet in length and weighing in at over three thousand pounds. Females are a bit smaller.
© 2009-2012 Patricia A. Michaels