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10 Facts About Walruses

Information About the Largest Pinniped

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Walruses are easily-recognizable marine animals due to their long tusks, obvious whiskers, and winkled brown skin. There is one species (and two subspecies) of walrus, and all live in cold regions in the Northern Hemisphere. Here you can learn some fascinating facts about walruses.

1. Walruses are related to seals and sea lions.

Steller Sea Lion / scazon, Flickr
Courtesy scazon, Flickr
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 infraorder 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.

2. Walruses are carnivores.

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.

3. Male walruses are larger than females.

According to the U.S. Fish and Wildlife Service, male walruses are about 20% longer and 50% heavier than females. Overall, walruses can grow to about 11-12 feet in length and weights of 4,000 pounds.

4. Both male and female walruses have tusks.

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 2.5 feet. These tusks are not used for finding or piercing food, but for making breathing holes in sea ice, anchoring to ice during sleep, and during competition between males over females.

5. The walrus's scientific name means "tooth walking sea horse."

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.

6. Walruses have more blood than a land mammal of their size.

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 - 2-3 times more blood than a terrestrial (land) mammal of their size.

7. Walruses insulate themselves with blubber.

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.

8. Walruses take care of their young.

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 3-5 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 2 years or even longer if the mother doesn't have another calf.

9. As sea ice disappears, walruses face increased threats.

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. While walruses are harvested by natives in Russia and Alaska, it appears from a 2012 study that an even greater threat than harvesting may be 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.

10. I Am the Walrus?

Why did John Lennon declare "I Am the Walrus"? The answer is more related to author Lewis Carroll than the marine animal. To learn more, check out this article from the About.com Oldies Music Guide!

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