Walruses, large marine mammals of the Arctic, are instantly recognizable by their prominent tusks. These impressive features are far more than just visual identifiers; they are integral to the walrus’s survival and interactions within its icy environment.
What Walrus Tusks Are
Walrus tusks are actually elongated upper canine teeth that grow throughout the animal’s life. They are primarily composed of dentin, a hard, calcified tissue similar to ivory, giving them strength and durability. Unlike most teeth, walrus tusks also contain nerves, providing sensory feedback during use.
Both male and female walruses possess tusks, though there can be notable differences in their size and shape. Male tusks tend to be longer, straighter, and stouter, reaching lengths of up to 1 meter (39 inches), while female tusks typically grow to about 80 centimeters (31.5 inches). Calves are not born with tusks; they emerge during their first summer or fall.
How Walruses Use Their Tusks
Walruses use their tusks for essential activities in their Arctic habitat. They use their tusks for “hauling out,” pulling their massive bodies out of the water onto ice floes or land. The tusks provide grip on slippery ice, helping them maneuver and stabilize their weight. This action is so fundamental that the walrus’s genus name, Odobenus, translates to “tooth-walker.”
Another function of their tusks involves interacting with ice. Walruses use their tusks to create and maintain breathing holes in ice sheets, accessing air while foraging underwater, even in ice up to 8 inches (20 cm) thick. They strike upwards with their tusks to fracture ice from below, creating openings. This ability expands their foraging range during winter and provides emergency access to the surface.
Though once thought to be for digging food, research shows tusks are not primarily used for this purpose. Instead, they use sensitive whiskers to locate clams and other benthic invertebrates on the seafloor, then create suction with their mouths to consume them. Tusks are not for direct foraging, but for other critical survival needs.
Walrus tusks also serve as weapons for defense against predators like polar bears and orcas, and in conflicts with other walruses. When threatened, walruses may form protective circles around their young, facing outward with their tusks. In disputes, particularly among males, tusks are used in fights to assert dominance and establish hierarchy, often resulting in scars and injuries.
Tusks play a role in social display and dominance within walrus herds. Their size and appearance can indicate age, health, and social status. Males often display their tusks by raising and turning their heads sideways; those with larger tusks typically hold a higher social ranking, influencing mating rights and access to resources.
Tusk Health and Longevity
The extensive use of walrus tusks in their environment leads to significant wear and tear over a walrus’s lifetime. Tusks can become worn down, chipped, or even broken due to their constant interaction with ice, rocks, and other walruses during conflicts. This wear reflects the animal’s age and the intensity of its activities.
Despite the continuous growth of walrus tusks, which compensates for some wear, severe damage can still occur. A damaged tusk can lead to life-threatening infections, particularly because the roots extend deep into the sinuses and near the brain. While wild walruses endure such wear, preventative measures like tusk capping have been used in managed care settings to mitigate excessive abrasion.