Introduction to Walrus
Walrus, a large, seal-like marine mammal that lives chiefly north of the Arctic Circle. A bull (male) walrus may grow 11 feet (3.4 m) long and weigh 3,000 pounds (1,360 kg). Walruses are protected from cold by a thick layer of fat called blubber and by a thick, wrinkled, almost hairless, tan skin.
Both male and female walruses have vibrissae, sensitive whiskers that they use to locate food along the ocean floor. The vibrissae grow to 6 inches (15 cm) in length, but are constantly being worn down. Walruses feed on mollusks, worms, crabs, and shrimp. The canine teeth of both sexes form long ivory tusks that extend downward from the upper jaw. A tusk is usually 10 to 15 inches (25 to 38 cm) long, but may grow to 40 inches (1 m) and weigh 12 pounds (5.4 kg). The walrus uses its tusks to haul itself onto ice floes, to cut through ice, and as weapons against predators. In addition, the male uses its tusks to fight other males; the male with the largest tusks is usually the leader of its herd.
Walruses are the only seals with tusks.Walruses have pharyngeal, or throat, pouches, which they can inflate to keep afloat while sleeping in the water. The pouches also serve as resonance chambers, allowing underwater communication.
During most of the year, males (bulls) and females (cows) live in different herds. During the breeding season, they gather on ice floes and rocky shores; the female typically bears one calf. A walrus lives for about 40 years.
Walruses are the prey of killer whales and polar bears. They are important to Eskimos who follow the traditional way of life; they eat walrus flesh and blubber and use the blubber oil for fuel. They use the hide as roofing, to make harnesses, and for other purposes. They carve decorative objects from the tusks.
The Atlantic walrus is found as far south as Labrador. It is hunted for its ivory, and its population is declining. The Pacific walrus lives in the region from the Bering Sea northward. Its population is thriving.
The walrus forelimb is specially adapted for swimming.Walrus Ways
Why Is It Easy to Recognize a Walrus?Walruses are the only pinnipeds with tusks. They are big animals, next in size to elephant seals.
Walruses live in the cold waters of the Arctic, North Atlantic, and North Pacific oceans. Their skin is very thick, with many folds and wrinkles. Walruses do not have much hair. But they do have a lot of blubber, which keeps them warm.
Like fur seals, walruses can walk on all fours. The rough bottoms of their flippers keep them from slipping If a walrus looks as if it is just standing in the water, it may be sleeping. Pouches on the sides of the male walrus’s neck fill with air. The air in the pouches helps keep the animal afloat. Female walruses do not have these pouches.
How Does a Walrus Use Its Tusks?A walrus uses its tusks to defend itself from enemies, such as polar bears. Sometimes, it also uses its tusks as hooks to haul out onto the ice. At other times, a walrus uses the tusks as anchors to hold onto the ice while floating in the water.
Tusks are also good for picking at ice and making breathing holes. Tusks can even help rescue a pup that has gotten stuck in an ice crack. For example, a mother might use her tusks to destroy a block of ice to free her stuck pup.
Most walruses have two tusks. These tusks are really the animal’s upper canine teeth. But what long teeth they are! The tusks may grow to be 39 inches (99 centimeters) long. Tusks continue to grow all during the animal’s life.
What—and How—Do Walruses Eat?Walruses like to be near their favorite food—clams. A walrus will swim along in shallow water, and when it finds a clam, it will use its tongue to form a vacuum. It sucks the clam into its mouth. Then it sucks out the meat and spits out the shell. For a walrus, it takes a few thousand clams to make one good meal.
Walruses also eat fish, worms, snails, crabs, and shrimp. Sometimes, walruses eat birds. They may even eat other seals and young whales. Although walruses find most of their food in shallow waters, they can dive for food, if they need to.
What Is Life Like in a Walrus Herd?Walruses like to be with other walruses. They spend most of their time in herds. A herd of walruses may drift along together on an ice floe. Or, the whole herd may haul out onto land.
There may be thousands of walruses in a herd. The animals pile up, one on top of the other. Fights sometimes break out. A large bull walrus may want a better spot in the crowd. He’ll throw back his head and point his tusks at a smaller animal. The message is clear: “Move over, or else!”
Among the herd are many walrus pups, called calves. Walrus mothers care for their calves for about two years. To protect her calf in the crowd, the mother holds it under her body and between her two front flippers.
The Atlantic walrus is Odobenus rosmarus rosmarus; the Pacific, O. r. divergens. Walruses make up the family Odobenidae. Along with seals, they make up the taxonomic group Pinnipedia.