Walruses are large marine mammals inhabiting frigid Arctic and sub-Arctic waters. Easily recognized by their prominent tusks and thick, wrinkled skin, these powerful pinnipeds spend much of their lives in shallow coastal areas and on ice floes. Their diet and feeding behaviors are distinctive, reflecting specialized adaptations for foraging on the seafloor.
Primary Food Sources
Walruses primarily eat benthic invertebrates, organisms living on or within the seabed. These bottom-dwelling creatures make up approximately 97% of their diet, making them highly specialized feeders. Their staple food is bivalve mollusks, such as clams and mussels, consumed in vast quantities. A single adult walrus can eat between 3,000 and 6,000 clams in one feeding session.
Beyond bivalves, walruses also feed on other invertebrates, including snails, sea cucumbers, marine worms, tunicates, and crustaceans like shrimp and crabs. These diverse prey items are typically found in shallow waters, usually at depths of 10 to 50 meters. Their substantial consumption of benthic organisms highlights their important role in the Arctic marine ecosystem.
How Walruses Forage
Walruses possess unique adaptations to efficiently find and consume prey on the ocean floor. Their most important sensory tools are highly sensitive whiskers, known as vibrissae. These vibrissae are richly supplied with nerves and blood, allowing walruses to detect subtle movements of buried prey as they root along the seafloor with their snouts. They move their muzzles close to the sediment, using whiskers to locate food.
Once prey is detected, walruses use a powerful suction feeding method to extract soft parts of bivalves from their shells. They create a vacuum with their mouths, sucking the animal out while often leaving intact shells behind on the seabed. To expose buried organisms, walruses may squirt jets of water from their mouths or nostrils, or use their foreflippers to stir up sediment. While their iconic tusks are prominent, they are primarily used for hauling out onto ice, social displays, or defense, not for digging for food.
Variations in Diet
While their diet is predominantly benthic invertebrates, walruses can exhibit opportunistic feeding behaviors. They may occasionally consume fish, such as polar cod, herring, or capelin, especially when preferred mollusk prey is less available. These instances are not their primary mode of feeding but show their adaptability to varying food resources.
On rare occasions, walruses have been observed preying on other marine animals. This can include seals, such as ringed and bearded seals, or scavenging on carrion like whale carcasses. These predatory or scavenging events are exceptions to their usual diet, often occurring during periods of food scarcity or when prey is readily accessible.