Walrus teeth are big because two of them have been turned into multi-purpose tools. The tusks are upper canine teeth that keep growing through life and can reach about a metre in length. They evolved mostly as social weapons and status symbols, and they double as ice picks. The rest of the walrus’s mouth is the opposite: a few small, flat teeth in an animal that swallows its food without chewing.

Both males and females carry tusks, which is unusual among tusked mammals. In males they are slightly longer and thicker. For the species overview, see our walrus hub.

Are walrus tusks teeth?

Yes. A walrus tusk is an upper canine, the same tooth as your “eye tooth”. It is rootless and keeps growing from an open pulp at its base, so a tusk lengthens throughout the animal’s life while wear and breakage take off the tip. In cross-section it shows growth rings that biologists use to estimate age. Walrus ivory is made of dentine, with a distinctive marbled, crystalline-looking core that carvers and customs officers use to tell it apart from elephant ivory.

Why did walrus tusks evolve to be so big?

The best explanation is competition within herds. Walruses live packed together by the hundreds or thousands, and they settle disputes over space and mates largely by display. The strongest males with the largest tusks typically dominate social groups, and Alaska’s Department of Fish and Game describes tusks being used in “mutual display”, with dominance going to the strongest animals. When bigger weapons mean more mates, evolution pushes them bigger generation after generation. Bulls also fight with them in the January–April rut, stabbing at the thick, lumpy skin of each other’s necks.

Females have tusks too, and they use them to defend calves and to claim space in the herd. That both sexes are tusked suggests the tusks also pay off in daily life, not only in mating contests.

What do walruses use their tusks for?

The hauling-out habit gave the walrus its scientific name; see do walruses walk on their teeth?

Do walruses chew their food?

Hardly at all. Walruses feed mostly on clams and other bottom animals. They find them with 400–700 sensitive whiskers that can tell shapes a few millimetres across, then seal their lips around the clam and suck the soft body out of the shell with powerful suction generated by the mouth and tongue. Researchers measured suction pressures of nearly −119 kPa underwater. A single feeding session can account for thousands of clams. With that system, a walrus has little need for cutting or grinding teeth, so the cheek teeth are small, simple pegs, often worn flat by sand.

How many teeth does a walrus have?

Walrus dentition is highly variable. A typical adult has only 18 teeth, although as many as 38 have been recorded. The usual set per side is one upper incisor, one upper canine (the tusk), one small lower canine and three cheek teeth (postcanines) above and below. Compared with a sea lion’s mouth full of pointed teeth for gripping fish, the walrus has traded teeth for suction.

Are male walrus tusks bigger than female tusks?

Yes, a little. Males’ tusks are slightly longer and much stouter, while females’ are more slender and often more curved. Pacific walruses also tend to have longer tusks than Atlantic walruses. Tusks are often broken or worn, so a given animal’s tusks rarely show the full potential length. For walruses with missing tusks, see are there walruses without tusks?

Why has walrus ivory been so valuable?

Because it carves beautifully. The 12th-century Lewis Chessmen are mostly carved from walrus ivory, and Arctic peoples have made tools, harpoon heads and art from it for thousands of years. Commercial hunting for ivory, blubber and hides drove walrus numbers down sharply in the 18th–20th centuries and nearly wiped out the Atlantic subspecies. Today commercial hunting is banned throughout the range, Indigenous subsistence hunting is regulated, and international trade in walrus ivory is controlled under CITES Appendix III.