Walruses are large Arctic marine mammals, instantly recognizable by their prominent tusks and whiskered snouts. Adult males can weigh over 2,000 kilograms, making them among the largest pinnipeds. Their imposing size often raises questions about their role in the marine ecosystem, particularly if they are predators. This article explores their unique dietary habits and feeding strategies.
What Walruses Primarily Eat
Walruses primarily consume benthic invertebrates, small animals living on or within the seafloor. These bottom-dwelling organisms make up approximately 97% of their diet, establishing walruses as specialized feeders. Common examples include clams, mussels, worms, snails, sea cucumbers, and crustaceans.
To sustain their massive bodies, walruses must consume vast quantities of these small organisms. An adult can eat 3% to 6% of its body weight daily, translating to 3,000 to 6,000 clams in a single feeding session. This reliance on abundant, individually small food sources distinguishes them from typical large marine predators.
How Walruses Find Food
Walruses use specialized adaptations to acquire their diet from the seafloor. Their most distinctive sensory tools are their whiskers, numbering 400 to 700 in 13 to 15 rows on their snouts. These highly sensitive whiskers, supplied with blood and nerves, enable walruses to detect prey even in murky, low-visibility waters.
To locate food, a walrus moves its snout along the bottom, rooting through sediment and using its whiskers to identify prey. Once detected, walruses employ a unique suction feeding method. They seal their lips around the invertebrate and rapidly pull their piston-like tongue back, creating a powerful vacuum. This extracts the soft parts, which the walrus swallows whole without chewing. While their tusks are used for breaking ice, hauling onto land, or defense, they are not typically used for hunting or digging.
Walruses and the Marine Food Web
While primarily specialized benthic feeders, walruses occasionally exhibit opportunistic predatory behavior. They have been observed preying on seals, particularly young or injured individuals, seabirds, or even fish in rare circumstances. These instances are uncommon and do not represent their main feeding habits. Some larger male walruses are known to habitually prey on seals, recognizable by their greater size and grease-stained skin.
Walruses serve as prey for a limited number of large marine animals, primarily polar bears and killer whales. Due to their size, tough hide, and tusks, adult walruses are challenging targets. Predators often favor easier prey like seals, and are more likely to target walrus calves or infirm animals. The walrus holds a unique position as a specialized feeder that occasionally preys on others, while also being part of the Arctic food chain.