Walruses belong to the Mammalian Order
Pinnipedia, in the family Odobenidae. Walruses are the only members
of this family. They are easily distinguishable from other
pinnipeds by their tusks, which are elongated canine teeth. The
walrus's scientific name is Odobenus rosmarus. The genus
name, Odobenus, means "one that walks with its teeth". This
refers to the walrus's common behavior of dragging itself over ice
flows with its tusks. The specific name, rosmarus, is
derived from the Scandinavian name for walrus.
Adult males are 10-12 feet long and can
weigh 2,000-3,000 pounds. Their tusks may reach a length of 3 feet
and weigh over 10 pounds. Females are 7-9 feet long and can weigh
1,500-2,000 pounds. Several inches of blubber and very thick skin
to help keep them warm. Walruses share anatomical features with sea
lions and true seals. Like Otariids, walruses can turn their hind
flippers forward and support their body for walking on land. But
like Phocids, they lack external ear flaps.
The walrus lives in the artic oceans
following the ice line as it expands and recedes on a yearly basis.
There it feeds on up to 4,000 clams in one feeding! Other
invertebrates include snails, mussels, starfish, urchins and sea
cucumbers. Walruses unearth food items on the ocean bottom by
squirting water out of their mouth. The stream of water drills the
mollusks hidden in the mud. Walruses also dine on a fish, and there
is one record of a walrus feasting on a seal pup.
A walrus's tusks are used for many
things including defense from polar bears, killer whales, and local
hunters. They also use them for social roles, pulling themselves up
onto the ice floes, and to create breathing holes in the ice.
They can dive 300 feet in the water to hunt for prey. Since there
is little light present at depths of 200-300ft, eyesight is not the
walrus's primary hunting sense. Its long whiskers, called
vibrissae, are used to feel around the ocean floor for prey species.
On land, they congregate in herds of 100
to over 1,000 animals. Males maintain harems of females. Walrus
calves climb atop their mothers to avoid getting crushed in these
large herds. Walruses bask in the sun to keep warm. Their skin
turns pink as blood rushes to fill the vessels closest to the
surface of the skin to warm up. The males have inflatable air sacs
on either side of their necks allowing them to make a bellowing
sound. This sound is used to warn other males and call females.
These air sacs also fill up with air like floatation devices so that
the walrus may vertically bob in the water to sleep. It is believed
that mating takes place in the water. Female walruses give birth to
a single calf on land. This calf weighs around 100 pounds.
Walruses can live up to 40 years.
There are two subspecies or races of
walrus: the Atlantic and Pacific. The Atlantic race was formerly
found as far south as Nova Scotia and occasionally Massachusetts.
This race is now endangered. Walrus numbers were reduced
drastically by commercial hunters until in 1972, the marine mammal
act protected them and made it so that only people native to the
land can hunt and kill a certain number of animals.