8 Facts About the Wonderful Walrus

Walruses are probably best known for their oversized tusks. In fact, the species' scientific name Odobenus rosmarus is Latin for “tooth walking sea horse.” There are two subspecies of these marine mammals: the Pacific walrus and the Atlantic walrus. They migrate north in the summer and south in the winter, inhabiting shallow areas of the Arctic primarily made of ice. Due to global warming and hunting, walruses are at risk.

Social animals, walruses usually congregate with members of the same sex. These blubbery carnivores feed on large quantities of small invertebrates. From their sensitivity to loud noises to their ability to find food in murky water with their vibrissae, discover the most fascinating facts about walruses.

1. Walruses Are Enormous

Walruses are large semi-aquatic pinnipeds. Of the two extant subspecies, Pacific walruses are heavier than Atlantic walruses, and males are larger and heavier than females. Walruses can grow to be nearly 12 feet in length and weigh as much as 4,000 pounds. 

Other than humans, the walrus only has two natural predators — orca whales in the water and polar bears on the ice. The calves are most vulnerable since adult walruses are capable of handling most predators.

2. They Use Their Tusks As Tools

Both male and female walruses have tusks, which are actually oversized canine teeth. They use their tusks — which can grow as long as 35 inches — as a weapon against predators and as a display of dominance. But they also use them for practical purposes — they allow the walrus to make breathing holes in the ice, and to remove chunks of ice that they use as a resting spot to access mollusks and marine invertebrates under the frozen surface.

3. They Are Adapted for Sea Life 

Walruses are marine mammals, and they have special adaptations for their life in the Arctic. Walruses have between two and three times more blood volume than a comparably sized land animal. This allows them to dive for long periods of time in cold water to reach food, storing as much oxygen in their blood and muscles as possible so they can stay underwater. Walruses are also able to reduce their heart rate when underwater to maintain warmth.

They also have a nearly 10-inch-thick layer of blubber under their skin that protects them from the cold Arctic waters.

4. They’re Strategic About Reproduction

When raising a youngster in the Arctic, animals need to be careful about timing to make sure that there are enough resources for both mother and young to survive and thrive. For walruses this means delayed implantation, where the fertilized egg does not immediately implant in the uterine wall.

Common among pinnipeds, the delay helps ensure that the female has the necessary energy and resources to raise a calf, which is 130 pounds and nearly four feet long at birth. Females only give birth to one calf every three years, and significant energy goes into raising a calf. Intensely protective, female walruses keep their offspring close for as long as three years.

5. They Can Rest on Water

Walruses work hard, swimming, diving, and moving chunks of ice around. So when it’s time for a rest, they can catch a nap just about anywhere — including floating in water. A study of sleeping patterns of captive walruses revealed that they can sleep for brief periods lying on the bottom of a pool, leaning against the side, or floating on the surface.

However, resting in water while paddling to stay afloat is not ideal, most of walruses' sleep time occurs on land.

6. They Find Food With Their Vibrissae

Though often mistaken for a mustache, the whiskers on a walrus are not hair, but incredibly sensitive vibrissae. Walruses have between 400 and 700 of these tactile organs lined up in 13 to 15 rows around the nose. They are used the same way cats, otters, rats, and other whiskered animals feel out the world around them. 

Walruses don’t have great vision, so to find prey on the dark ocean floor they rely on their vibrissae. The importance of these whiskers can't be understated, since walruses use them to find about 50 pounds of food a day.

7. They Are Sensitive Creatures

Walruses look big and tough, but they can be startled quite easily. Sensitive to sights, sounds, and odors from machines, like planes and boats, or humans, walrus herds will sometimes stampede into the water to escape a real or perceived danger. 

This is particularly hazardous for animals on a haulout site. Walruses rely on terrestrial and sea ice haulout sites to rest, nurse their calves, and go through their molt. When frightened, walruses may leave a site and never return. And calves, which are particularly vulnerable, may become separated from their mothers or trampled during stampedes and not survive.

8. They Are at Risk

A keystone species in their Arctic habitat, walruses are classified as vulnerable by the IUCN Red List of Threatened Species. The primary threats to walruses are global warming and hunting.

These large pinnipeds rely on sea ice for haulouts. In areas where ice is depleted due to global warming, Pacific walruses are forced to gather in larger numbers on land and to travel greater distances to find food, putting the species at increased risk. Increases in shipping, oil and gas exploration, and tourism in the Arctic is causing disturbances among Atlantic walruses, which may lead to more stampedes. The increase in industrial activity also puts walruses at an increased risk due to oil spills.

The harvesting of walruses has had a major impact on the population of Pacific walruses for over 200 years. Subsistence hunting is regulated by quota in Canada and Greenland, while in Norway and Russia, Atlantic walruses are protected from harvest.