Walruses possess a dental structure that extends beyond their well-known tusks. These large marine mammals have other teeth, which play a distinct role in their feeding habits.
The Prominent Tusks
Walrus tusks are elongated upper canine teeth, growing significantly throughout the animal’s life. They are primarily composed of dentine, a hard, bony tissue, and covered by a thin layer of cementum. These structures serve multiple functions for the walrus in their icy habitat.
Walruses use their tusks to haul their bodies out of the water onto ice floes or rocky shores, a behavior that earned them the scientific name “tooth-walker.” They also employ their tusks to break and maintain breathing holes in thick ice, providing access to air while foraging beneath the surface. Beyond practical uses, tusks are important for social interactions; males use them in displays of dominance and during fights for mating opportunities. Tusks also offer a form of defense against potential predators.
Beyond the Tusks: Other Teeth
Beyond their prominent tusks, walruses possess other teeth, though these are far less conspicuous. Most walruses have around 18 teeth, which can include molars and premolars. These smaller teeth are flat or peg-like in shape.
Despite having these other teeth, walruses do not primarily use them for chewing or crushing the hard shells of their prey. Instead, walruses are suction feeders, utilizing their powerful tongues to create a vacuum and suck the soft parts of invertebrates, such as clams and mollusks, directly out of their shells. While some wear may be observed on their cheek teeth, this results from abrasion by sand ingested during feeding, rather than from actively crushing shells.
Tusk Growth and Development
Both male and female walruses develop tusks, which grow continuously throughout their lifespan. Male tusks tend to be longer, straighter, and more robust than female tusks. Walrus calves are not born with visible tusks; these teeth erupt during their first summer or fall.
The continuous growth of tusks means their length offers clues about a walrus’s age. Tusks grow for approximately 15 years, though in males, growth may continue beyond this period. Consistent use leads to wear and tear, and fractures can occur, particularly in adult males due to their more aggressive social interactions.