What Exactly is a Walrus? Are They Mammals?

  • Post last modified:September 4, 2022
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Walruses are impressive and iconic mammals. They have several characteristics that make them easily distinguishable, but where exactly do they fit in the animal kingdom?

A walrus is a marine mammal. The walrus is the only living member of the family Odobenidae, within the class Pinnipedia, order Carnivora, class Mammalia, and phylum Chordata. Walruses spend their life in and out of the water, unlike other marine mammals which are fully aquatic.

Keep on reading to find out more about what walruses are, how to refer to them, and what characteristics they have.

Are Walrus Mammals?

Yes, walrus are mammals. They belong to the class Mammalia and have the basic characteristics that we would expect from a mammal such as being warm-blooded, having fur or hair, having a complex brain (due to the presence of a neocortex), and producing milk for their young1 (source: Britannica).

More specifically, walrus are marine mammals. This means that walruses are dependent on the ocean to survive2 (source: SeaWorld). They are well adapted to the water and despite their enormous size, they can swim at speeds of up to 35 km/h (22mph).

However, they are not fully aquatic, as they spend one-third of their life outside of water on average3 (source: SeaWorld).

Are Walrus Vertebrates?

Yes, walrus are vertebrates which means that they do have a backbone (vertebral column). They have many of the typical characteristics of vertebrates, for example, two pairs of limbs, in the form of flippers, a distinct head, and bi-lateral symmetry which means that they look the same on the left as the right4 (source: Britannica).

If you want to find out more about these animals, check out our top walrus facts.

Are Walrus Related to Seals?

Yes, walruses and seals are related, they belong to the same taxonomic group called Pinnipedia. This means that Walruses and seals are “pinnipeds”, alongside sea lions5 (source: Wikipedia). Pinnipeds are carnivorous marine mammals that have both front and rear flippers6 (source: The Marine Mammal Centre).

It is relatively easy to tell walruses apart from seals and sea lions. This is because walruses grow much larger, they can weigh between 800kg and 1700kg which is around twice the size of a typical seal7 (source: Live Science) (with the exception of the enormous elephant seal).

If in doubt, a key identifying feature of a walrus is its elongated teeth called tusks8 (source: J.N. Winer, et al, Journal of Comparative Pathology, Vol. 155, Issues 2–3, pp.242-253, 2016). Despite popular belief, these are rarely used for fighting, see our full article to find out exactly why walrus have tusks.

Where Does the Walrus Get its Name?

The name “walrus” originates from a Danish word. The Danes used to refer to walrus as “hvalros” which means “sea cow” or “sea horse”.

What is a Group of Walruses Called?

A group of walruses is called a herd. Walruses tend to gather in large herds, with estimated sizes of more than 55,000 individuals in 20189 (source: A.S. Fischbach, et al, The Journal of Wilflife Management, Vol. 86, Issue 6, 2022). However, walruses can gather in herds as small as 10 individuals10 (source: SeaWorld).

A “nursery herd” is when a group of baby walruses (that are more than two days old) gather together. A nursery herd is separate from adult herds. As many as 200 baby walruses can gather in a nursery herd, however, the herd size is usually between 20 to 50 walruses11 (source: SeaWorld).

What is a Baby Walrus Called?

A baby walrus is often called a calf. A female walrus is called a “cow” and a male is called a “bull”12 (sources: SeaWorld and National Geographic).

What is Plural for Walrus?

The plural form of walrus is either walrus or walruses. The usage of the plural form is often personal preference. However, “walrus” is often used when referencing multiple walruses as a collective13 (source: Dictionary.com).

Related Questions

Are Walrus Fish?

No, walruses are not fish, they are marine mammals. There are many differences between fish and marine mammals. For example, walruses do not have gills whereas fish do14 (sources: N.Kohno, Journal of Vertebrate Paleontology, Vol. 26, Issue 2, 2006 and Wikipedia).

Are Walrus Reptiles?

No, walruses are not reptiles. Walruses are part of the Mammalia class, whereas reptiles are found within the Reptilia class. There are numerous differences between mammals and reptiles. For example, unlike reptiles, mammals produce milk, have fur or hair, and have middle ear bones15 (source: Wikipedia).

What Family Does the Walrus Belong To?

The walrus belongs to the family Odobenidae. The family Odobenidae used to be widespread, however, the walrus is the only surviving member16 (source: N.Kohno, Journal of Vertebrate Paleontology, Vol. 26, Issue 2, 2006).


  • Ryan Charles

    Ryan is a research scientist with a MSc in marine biology from Bangor University. His research focuses on developing an understanding of threatened species to assist conservation efforts. He is particularly interested in sharks and their relatives, alongside whales and other marine mammals.

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