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Walrus

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The walrus, scientifically known as *Odobenus rosmarus*, is a massive marine mammal. It belongs to the order Carnivora. It is also a pinniped, which is a group of sea-dwelling mammals.

Morse IRSNB
Morse IRSNB

The walrus is unique because it is the only living member of the family Odobenidae. This family was once much larger and more diverse. It once included at least twenty different species. Today, the walrus is a relict species, meaning it is the last survivor of its lineage. Walruses are considered a keystone species in the Arctic. This means they play a vital role in their marine ecosystem.

Walrus2
Walrus2

Walruses live in the Arctic Ocean and subarctic seas. They prefer shallow waters located above the continental shelves.

WalrusBreathing
WalrusBreathing

Most of their life is spent on sea ice or in the water. They search for food on the ocean floor. They specifically look for benthic bivalve molluscs, which are shell-based animals living in the sediment. To find these, they use a specialized feeding mechanism involving suction. They also use their highly sensitive whiskers, called vibrissae, to feel for prey. These bristles are attached to muscles and nerves. They can detect the shape and size of objects in the dark.

Walrus - Kamogawa Seaworld - 1
Walrus - Kamogawa Seaworld - 1

There are two recognized subspecies of the walrus. The first is the Atlantic walrus, *O. r. rosmarus*. It lives in the Atlantic Ocean. The second is the Pacific walrus, *O. r. divergens*. It lives in the Pacific Ocean.

Noaa-walrus12
Noaa-walrus12

These two groups have fixed genetic differences. This suggests they do not mix much. Scientists believe they separated about 500,000 to 785,000 years ago. Some researchers once thought there was a third subspecies in the Laptev Sea. However, most now agree that group is actually of Pacific origin.

Herd of Pacific walrus resting
Herd of Pacific walrus resting

Evolutionary history shows that walruses have changed greatly over millions of years. Genetic evidence suggests they descended from a caniform ancestor. This ancestor was closely related to modern bears. The odobenids and otariids separated from phocids about 20 to 26 million years ago. The modern walrus likely evolved from a tropical or subtropical ancestor. As these ancestors moved north, they adapted to much colder conditions.

Fossil walrus skull (Odobenus rosmarus)
Fossil walrus skull (Odobenus rosmarus)

This adaptation included the development of thick blubber for warmth.

Walruses are among the largest pinnipeds in the world. They are only smaller than the two species of elephant seals.

Walrus2
Walrus2

Most walruses weigh between 800 and 1,300 kilograms. However, some large Pacific males can weigh more than 1,500 kilograms. The Atlantic subspecies is generally 10 to 20 percent smaller than the Pacific subspecies. Females are also smaller, weighing about two-thirds as much as males. To stay warm, they use a layer of blubber under their skin. This fat can be up to 10 centimeters thick.

Walrus - Kamogawa Seaworld - pup -1
Walrus - Kamogawa Seaworld - pup -1

One of the most famous features of the walrus is its tusks. These are actually elongated canine teeth. Both males and females have them. They can reach 1 meter in length and weigh up to 5.4 kilograms.

BLW Teeth in the skull of a large Walrus
BLW Teeth in the skull of a large Walrus

Males have thicker and longer tusks. They use them for fighting and social dominance. Walruses also use tusks to help them climb onto ice. They can even use them to maintain breathing holes in the ice. While they were once thought to be digging tools, research shows they actually drag through sediment. The snout is used for the actual digging.

Walrus - Kamogawa Seaworld - 1
Walrus - Kamogawa Seaworld - 1

Human history is closely tied to the walrus. Many indigenous Arctic peoples have used the animal for meat, fat, skin, and bone.

Walrus on Carta Marina
Walrus on Carta Marina

In the 19th and early 20th centuries, hunting increased significantly. People hunted them for blubber, leather, and ivory. This caused the population to drop rapidly across the Arctic. While populations have rebounded somewhat, some groups remain at low levels. The name "walrus" likely comes from Germanic languages. It may mean "horse-whale" in Old Norse. The scientific name *Odobenus* comes from Greek words meaning "tooth-walker." This describes how they use their tusks to pull themselves out of the water.

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🖼️ Images & Media (13)
File:Walrus on Carta Marina.jpeg
Walrus on Carta Marina.jpeg
File:Fossil walrus skull (Odobenus rosmarus).jpg
Fossil walrus skull (Odobenus rosmarus).jpg
File:Walrus2.jpg
Walrus2.jpg
File:Morse IRSNB.JPG
Morse IRSNB.JPG
File:WalrusBreathing.jpg
WalrusBreathing.jpg
File:BLW Teeth in the skull of a large Walrus.jpg
BLW Teeth in the skull of a large Walrus.jpg
File:Armand de Montlezun (1841-1914) Bacalum Morse.jpg
Armand de Montlezun (1841-1914) Bacalum Morse.jpg
File:Noaa-walrus12.jpg
Noaa-walrus12.jpg
File:Walrus - Kamogawa Seaworld - pup -1.jpg
Walrus - Kamogawa Seaworld - pup -1.jpg
File:Лежка моржей на острове Нортбрук.jpg
Лежка моржей на острове Нортбрук.jpg
File:Herd of Pacific walrus resting.png
Herd of Pacific walrus resting.png
File:Walrus - Kamogawa Seaworld - 1.jpg
Walrus - Kamogawa Seaworld - 1.jpg

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