Walruses use their tusks to haul out of the sea, not to dig
The walrus's scientific name, Odobenus, joins Greek words for tooth and walk, because observers watched the animals heave themselves onto ice with their tusks. Those tusks, grown by both sexes and up to a metre long, also keep breathing holes open and settle rank among males, but they are not shovels.
Wear patterns show that walruses drag their tusks through sediment while digging for clams with the top of the snout. Finding prey falls to a moustache of 400 to 700 stiff whiskers in 13 to 15 rows, each wired with nerves and blood vessels and able to tell apart shapes just 3 millimetres thick. Bulging eye muscles let the animal push its eyes out to look forward and upward, though its sight suits short distances. A throat air sac acts as a float, so a walrus can bob upright and doze in the water.
The walrus is the last survivor of a family that once held at least twenty species. It has two widely accepted subspecies, Atlantic and Pacific, which split roughly 500,000 to 785,000 years ago; a Laptev Sea group once considered a third turned out to be of Pacific stock. Big Pacific males can pass 2,000 kilograms, and among pinnipeds only elephant seals are larger. Their skin is up to 10 centimetres thick on a male's neck, over blubber up to 15 centimetres deep, and it blanches almost white in cold water as blood vessels tighten.
Walruses once bred as far south as Sable Island off Nova Scotia, and fossils appear near San Francisco and North Carolina. Heavy hunting for blubber, ivory, leather and meat in the nineteenth and early twentieth centuries cut numbers across the Arctic, and Atlantic and Laptev populations remain low and scattered. Arctic Indigenous peoples have long relied on the animal for food, skin, ivory and bone.
The English name probably comes from Old Norse words for whale and horse, reversed in Dutch as walros. The older word morse passed through Slavic from Finno-Ugric languages, and its echo of the Latin for bite may have helped paint the walrus as a monster. Olaus Magnus drew one on his Carta Marina in 1539.
Source: Walrus
