Walruses are large marine mammals inhabiting the Arctic Ocean and subarctic seas, primarily around the North Pole. They are recognized by their prominent tusks, thick skin, and considerable bulk. Adult Pacific males can weigh over 2,000 kilograms (4,400 pounds), making them among the largest pinnipeds. Walruses spend much of their lives in shallow waters over continental shelves or on sea ice, where they rest and forage.
Primary Predators
Walruses, despite their imposing size, face predation from two main Arctic predators: polar bears and orcas. Adult walruses are rarely targeted due to their formidable defenses, but young, sick, or isolated individuals are more vulnerable.
Polar bears are opportunistic hunters that primarily target seals, but prey on walruses when seals are scarce. They often stalk walrus herds on ice, seeking to separate a young, weak, or sick animal. On land, polar bears may attempt to overpower a walrus, though even a small calf has a heavily constructed skull. Some accounts suggest polar bears intentionally provoke walrus herds into stampeding into the water, hoping calves will be trampled, making them easier prey.
Orcas, also known as killer whales, are highly effective marine predators of walruses. They often hunt cooperatively, using sophisticated strategies. Orcas may encircle and repeatedly strike walruses with their tails, or ram them from below, to disorient and injure them. Walruses are more agile in water than polar bears, but orcas are powerful and pursue them relentlessly. Orcas typically focus on calves or smaller walruses, which are less able to defend themselves.
Walrus Defenses Against Predators
Walruses possess several physical attributes and behavioral strategies to protect themselves. Their most distinctive defense is their tusks, elongated canine teeth present in both males and females. These tusks can grow up to 1 meter (3 feet) long and are used to fend off attackers like polar bears or orcas, potentially causing fatal injuries.
Beyond their tusks, walruses have thick skin and a substantial layer of blubber. This blubber provides insulation and acts as a natural armor against bites and blows, making it difficult for predators to inflict serious harm. Walruses also use vocalizations, such as loud whistles, barks, and roars, to alert their peers to danger and intimidate potential threats.
Walruses are social animals that often gather in large herds, sometimes numbering in the thousands. This communal behavior offers safety in numbers, as a tightly packed group is harder for a predator to target. When threatened, they may form a defensive huddle, protecting the most vulnerable individuals. Walruses are also agile swimmers, using their powerful hind flippers to evade predators in their aquatic environment. They seek refuge in water or on sturdy ice floes, where they are less vulnerable than on land.