8 Facts About Walruses

Walrus colony on shore of Round Island, Alaska

Jeff Foott / Getty Images

Walruses are easily recognizable marine animals due to their long tusks, obvious whiskers, and wrinkled brown skin. There ​are one species and two subspecies of walrus, all living in cold regions in the Northern Hemisphere. Discover more fascinating facts about walruses, the largest pinniped.

01
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Walruses Are Related to Seals and Sea Lions

Sea Lions in Morro Bay, California
Sea Lions.

Monica Prelle

Walruses are pinnipeds, which classifies them in the same group as seals and sea lions. The word pinniped comes from the Latin words for ​wing- or fin-footed, in reference to the fore- and hindlimbs of these animals, which are flippers. There is disagreement over the classification of the taxonomic group Pinnipedia. It is considered by some as its own order, and by others as an infra-order under the order Carnivora. These animals are well adapted for swimming, but most—especially "true" seals and walruses—move awkwardly on land. Walruses are the only member of their taxonomic family, Odobenidae.

02
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Walruses Are Carnivores

Walrus underwater in the shallows

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Walruses are carnivores that feed on bivalves such as clams and mussels, as well as tunicates, fish, seals, and dead whales. They often feed on the ocean bottom ​and use their whiskers (vibrissae) to sense their food, which they suck into their mouths in a swift motion. They have 18 teeth, two of which are canine teeth that grow to form their long tusks.

03
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Male Walruses Are Larger Than Females

A male and female walrus lay amongst ice

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Walruses are sexually dimorphic. According to the US Fish and Wildlife Service, male walruses are about 20 percent longer and 50 percent heavier than females. Overall, walruses can grow to about 11 to 12 feet in length and weights of 4,000 pounds.

04
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Both Male and Female Walruses Have Tusks

Skull of a walrus

S.-E. Arndt / Getty Images 

Both male and female walruses have tusks, although a male's can grow to 3 feet in length, while a female's tusks grow to about 2 1/2 feet. These tusks are not used for finding or piercing food, but for making breathing holes in sea ice, anchoring to the ice during sleep, and during competitions between males over females.

The walrus's scientific name is Odobenus rosmarus. This comes from the Latin words for "tooth-walking sea-horse." Walruses can use their tusks to help haul themselves up onto the ice, which is likely where this reference came from.

05
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Walruses Have More Blood Than a Land Mammal of Their Size

A polar bear looks up from its kill as walrus blood soaks the ice

Paul Souders / Getty Images

To prevent oxygen loss underwater, walruses can store oxygen in their blood and muscles when they dive. Therefore, they have a large volume of blood—two to three times more blood than a terrestrial (land) mammal of their size.

06
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Walruses Insulate Themselves With Blubber

A rotund walrus looking up from a snowy landscape

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Walruses insulate themselves from cold water with their blubber. Their blubber layer fluctuates according to time of year, the animal's life stage and how much nutrition it has received, but may be as much as 6 inches thick. Blubber not only provides insulation but can help make the walrus more streamlined in the water and also provides an energy source during times when food is scarce.

07
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Walruses Take Care of Their Young

A mother walrus and her pup

Galatee Films / Disney Enterprises

Walruses give birth after a gestation period of about 15 months. The gestation period is made longer by a period of delayed implantation, in which the fertilized egg takes three to five months to implant into the uterine wall. This makes sure that the mother has the calf at a time when she has the necessary nutrition and energy, and that the calf is born during favorable environmental conditions. Walruses usually have one calf, although twins have been reported. The calf weighs about 100 pounds at birth. Mothers are strongly protective of their young, who may stay with them for two years or even longer if the mother doesn't have another calf.

08
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As Sea Ice Disappears, Walruses Face Increased Threats

Walrus males in a herd or colony near the shoreline

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Walruses need ice for hauling out, resting, giving birth, nursing, molting, and protecting themselves from predators. As the world climate warms, there is less availability of sea ice, especially in the summer. During this time, sea ice may retreat so far offshore that walruses retreat to coastal areas, rather than floating ice. In these coastal areas, there is less food, conditions may become crowded, and the walruses are more susceptible to predation and human activities. Although walruses are harvested by natives in Russia and Alaska, a 2012 study shows that an even greater threat than harvesting may be the stampedes that kill young walruses. When fearing a predator or human activity (such as a low-flying aircraft), walruses may stampede and trample calves and yearlings.