Walruses are large marine mammals inhabiting the cold, shallow waters of the Arctic and Subarctic regions. Easily recognized by their prominent tusks and sensitive whiskers, their diet and feeding behaviors are crucial for survival in these challenging environments. Their specialized approach to finding and consuming food highlights unique adaptations that set them apart from other marine animals.
Primary Diet and Key Prey
The diet of the walrus primarily consists of benthic invertebrates, meaning animals that live on or in the seafloor. Bivalve mollusks, particularly clams, are a preferred food source, often making up the majority of their diet. Walruses also consume other soft-bodied organisms, including worms, sea cucumbers, snails, and crustaceans such as soft-shelled crabs and shrimp.
While predominantly bottom-dwellers, walruses are opportunistic feeders. They may occasionally supplement their diet with slow-moving fish, such as polar cod, or scavenge on carcasses. Rarely, larger Pacific walrus males may prey on seals and seabirds.
Given their massive size, adult walruses consume substantial quantities of food daily, estimated to be between 3% and 6% of their body weight. For example, a 2,000-kilogram walrus could eat 60 to 120 kilograms daily to sustain its energy and blubber reserves. They often feed twice daily, with a single session involving thousands of clams (3,000 to 6,000 bivalves). This high intake maintains their thick blubber layer, providing insulation and energy in their cold environment. Their diet varies seasonally, with increased consumption in summer and fall to build reserves for winter and spring.
Specialized Foraging Methods
Walruses have unique adaptations to locate and extract prey from the murky seabed. Their highly sensitive whiskers, called vibrissae, are primary sensory tools. Numbering 400 to 700 in 13 to 15 rows around their snout, these vibrissae detect subtle movements and shapes of buried invertebrates even in low visibility. As they forage, walruses move their snouts along the seafloor, using whiskers to sweep and feel for prey.
Once prey is detected, walruses use a suction feeding mechanism to extract soft tissues from bivalve shells. They create a vacuum by rapidly retracting their tongue within their palate, pulling the clam’s siphon or foot into their mouth. This suction extracts soft parts without crushing shells, which are typically discarded. Walruses swallow soft invertebrates whole.
To expose buried prey, walruses may root through sediment with their snouts, similar to a pig, or squirt water jets from their mouths to dislodge burrowing organisms. They may also use their foreflippers to uncover food.
While prominent, tusks are primarily used for breaking ice, hauling out onto ice or land, and for social interactions, not for digging food from the seabed. Walruses forage in shallow waters, usually 10 to 50 meters deep, but can dive deeper.