Walrus (Odobenus rosmarus): Facts, Tusks, Size and Diet

What does a walrus look like?

A walrus is easy to recognize. It has a massive, wrinkled body, a small head with tiny eyes, a broad muzzle covered in stiff whiskers, and two long ivory tusks that point down from the upper jaw. Both males and females have tusks. They are enlarged upper canine teeth that keep growing for most of the animal’s life and can reach about 1 m (3.3 ft) in the largest bulls. Why walruses carry them is explained in What are walrus tusks for?

The whiskers, or vibrissae, are just as important. A walrus has about 400–700 of them in 13–15 rows on its muzzle. They are thick, sensitive and connected to nerves and muscles, so a walrus can feel tiny objects on the dark seafloor.

The skin is thick and almost hairless, with only short, sparse fur. It is usually up to about 2–4 cm (1–1.5 in) thick, but on the neck and shoulders of old bulls it can reach about 10 cm (4 in) and becomes covered in knobby bumps called bosses. Underneath lies a layer of blubber up to about 15 cm (6 in) thick. Walruses change color with temperature. In icy water their skin blood vessels close down and they look pale gray or almost white, while on a warm beach they flush cinnamon brown to pink.

Walruses mix features of the two other pinniped families. Like sea lions, they can turn their hind flippers forward and walk on all fours on land. Like true seals, they have no external ear flaps and swim mainly by sweeping their hind flippers and body. The seal vs sea lion comparison explains these differences.

How big is a walrus?

The walrus is the third-largest pinniped, after the two elephant seals. Adults are about 2.2–3.6 m (7–12 ft) long, and males are much bigger than females.

Atlantic walruses are about 10–20% lighter than Pacific walruses and have slightly shorter tusks. The heaviest reliably weighed walrus was a Pacific bull of about 1,883 kg (4,151 lb). More detail is in How big is a walrus?

Atlantic and Pacific walruses

Scientists recognize two subspecies. The Pacific walrus (O. r. divergens) lives in the Bering and Chukchi seas between Alaska and Russia and is by far the more numerous. The Atlantic walrus (O. r. rosmarus) lives from the Canadian Arctic and Greenland east to Svalbard, Franz Josef Land and the western Russian Arctic. Genetic studies suggest the two have been separated for roughly half a million years or more.

A third, isolated group lives year-round in the Laptev Sea off northern Siberia. It was once named a separate subspecies, but genetic work shows it comes from Pacific walruses, and it is now usually grouped with them.

Where do walruses live?

Walruses live in the Arctic and subarctic seas of the Northern Hemisphere. They need shallow water over the continental shelf, usually less than about 80 m (260 ft) deep, so that they can reach the seafloor to feed, and they need somewhere to rest between feeding trips. Ideally that is drifting pack ice thin enough to break through but strong enough to hold their weight. When there is no ice, they haul out on beaches, rocky islands and gravel spits.

Many Pacific walruses migrate with the ice. They spend the winter on the pack ice of the Bering Sea, where they also mate. In spring, females and calves ride the retreating ice north through the Bering Strait into the Chukchi Sea, while many adult males stay behind and spend the summer at land haul-outs in Bristol Bay, Alaska, and the Gulf of Anadyr, Russia. In autumn, the herds move south again ahead of the new ice. Atlantic walruses make shorter seasonal movements around Hudson Bay, Baffin Bay, Greenland, Svalbard and the Barents and Kara seas.

Walruses once lived much farther south. Atlantic walruses bred on Sable Island off Nova Scotia and in the Gulf of St. Lawrence until they were wiped out by hunting in the 18th century, and a population in Iceland vanished after Norse settlement.

What do walruses eat?

Walruses are carnivores that feed mainly on clams and other invertebrates living on or in the seafloor. They also eat snails, worms, sea cucumbers, shrimp, crabs, tunicates and soft corals, and animals from more than 60 genera have been recorded in their diet. A few walruses, mostly big males, also eat seals.

A walrus feeds by swimming head down along the bottom, feeling for prey with its whiskers. It blasts sediment away with jets of water squirted from its mouth or by waving a flipper, then seals its lips around a clam and pulls back its piston-like tongue to suck out the soft body, leaving the shell behind. Adults eat about 3–6% of their body weight per day, and a single feeding session can involve thousands of clams. The details are in What do walruses eat?

Behavior: herds, haul-outs and sounds

Walruses are very social. They rest in tightly packed groups that range from a few animals to tens of thousands, often lying on top of each other. Outside the breeding season, males and females usually live in separate herds. Within a herd there is a pecking order based on body size and tusk length. Walruses settle disputes over resting spots by raising their heads to show off their tusks, and the smaller animal usually gives way.

They are also among the noisiest pinnipeds. Walruses grunt, bark, roar and whistle. Walruses, especially males, have inflatable air sacs in the throat that help them float upright while resting at sea and add a ringing, bell-like tone to the males’ calls. In the breeding season, males “sing” underwater for long periods with knocks, taps, whistles and bell sounds to attract females and warn rivals.

Walruses can sleep in the water, floating with their throat pouches inflated, or hang from the edge of an ice floe by hooking their tusks over it.

Reproduction and calves

Walruses mate in the water between January and March, near the ice where females gather. After mating, the fertilized egg pauses for about three to four months before it implants, so the whole pregnancy lasts about 15–16 months, one of the longest among mammals. Calves are born the following year between April and June, usually on sea ice.

A newborn calf weighs about 45–75 kg (100–165 lb) and can swim almost at once. The bond between mother and calf is the longest of any pinniped. Calves nurse for more than a year, can suckle in the water as well as on the ice, often ride on their mother’s back, and usually stay with her for about two years. Mothers defend their calves fiercely.

Because a female cannot become pregnant again until her calf is weaned, she gives birth at most once every two years, often less. That is the slowest breeding rate of any pinniped, so walrus populations recover only slowly from losses. Females can breed from about 5–7 years old, while males are mature by about 7–10 years but rarely win the chance to mate until about 15.

Lifespan, predators and threats

Walruses usually live about 20–30 years in the wild, and some reach about 40. Thanks to their size and tusks, adults have only two natural predators: the polar bear and the orca. A polar bear rarely tackles a healthy adult and may be badly injured by one. Bears usually charge resting herds and catch calves or weak animals in the panic, while orcas attack walruses in the water.

The biggest modern threat is the loss of sea ice. Since about 2007, summer ice in the Chukchi Sea has often retreated far north of the shallow feeding grounds, so tens of thousands of Pacific walruses come ashore instead. In September 2014, an estimated 35,000 crowded onto one beach near Point Lay, Alaska. Such haul-outs are far from the best feeding areas, and when a herd panics because of a bear, a low aircraft, a boat or people, calves can be trampled in the rush to the water.

Other pressures include shipping and industrial activity in a warming Arctic, pollution, and changes in the seafloor communities walruses feed on. Indigenous communities in Alaska, Russia, Canada and Greenland still harvest walruses for food and ivory under regulated limits.

Conservation status

The IUCN Red List has classified the walrus as Vulnerable since 2016, mainly because of the projected loss of sea ice, with the population trend listed as unknown. The assessment estimated about 112,500 mature walruses worldwide. Pacific walruses number in the low hundreds of thousands, while Atlantic walruses number only in the tens of thousands, split into several separate stocks. Walruses are very hard to count, so all estimates are uncertain.

Commercial hunting in the 18th to 20th centuries cut walrus numbers sharply across the Arctic and nearly wiped out the Atlantic walrus. Protection has brought some recoveries. In Svalbard, where walruses had almost disappeared by 1952, a ban on hunting allowed numbers to grow to about 5,500 by 2018. Walruses are protected in the United States by the Marine Mammal Protection Act of 1972, and international trade in walrus ivory is controlled under CITES.

Walruses and people

The walrus has been central to the lives of Arctic peoples such as the Yupik, Chukchi and Inuit for thousands of years, providing meat, oil, skin for boats and ivory for tools and carvings. In medieval Europe, walrus ivory was a prized material, and most of the famous 12th-century Lewis Chessmen, found in Scotland, are carved from it. The name walrus probably comes from Old Norse words for “whale” and “horse”.

Wandering walruses have become celebrities in Europe. “Wally” traveled from Ireland to Wales, France, Spain and the Isles of Scilly in 2021, and “Thor” led the town of Scarborough in England to cancel its New Year’s Eve fireworks in 2022. In 2022 Norway euthanized “Freya”, a young female in Oslo Fjord, after crowds repeatedly came too close. Walruses are among the classic Arctic animals, and anyone who meets one, at home or in the Arctic, should keep well back and never come between a walrus and the water.