The Arctic is home to the polar bear and the narwhal, two iconic species whose lives are shaped by the region’s sea ice. A common question is whether these predators and prey interact. Understanding their distinct roles in the Arctic food web provides insight into this dynamic relationship.
Polar Bear Hunting Strategies and Diet
Polar bears are specialized predators, primarily relying on the fat-rich blubber of seals for sustenance. Ringed and bearded seals constitute the bulk of their diet, providing the high-calorie intake necessary to thrive in cold environments. These bears possess a sense of smell capable of detecting seals from a considerable distance, even under layers of snow and ice.
A common hunting method involves patiently waiting by a seal’s breathing hole in the ice, ambushing the seal when it surfaces for air. Polar bears also stalk seals resting on the ice, utilizing snowdrifts and ice ridges for camouflage and moving with stealth before a final charge. Additionally, they may target seal dens hidden beneath the snow to prey on pups.
Narwhal Habitat and Behavior
Narwhals are unique toothed whales, instantly recognizable by the male’s long, spiraled tusk, an elongated canine tooth. These Arctic inhabitants primarily reside in the waters of Canada, Greenland, and Russia. They are exceptional deep divers, capable of descending to depths of over 2,300 meters (7,780 feet) and remaining submerged for up to 25 minutes, particularly during winter when they feed more intensively.
Their diet is specialized, consisting mainly of Arctic cod, Greenland halibut, and squid, which they are believed to consume by sucking them into their mouths. Narwhals migrate seasonally, moving to ice-free summering grounds, often in shallow coastal waters, then to deeper offshore waters under thick pack ice during winter. While they navigate the ice using natural leads and cracks, they can become vulnerable if these openings freeze over, leading to entrapment.
Rare Encounters: Polar Bears and Narwhals
While polar bears primarily hunt seals, their opportunistic nature means they will occasionally prey on or scavenge other marine mammals, including narwhals. These encounters are not a regular part of their diet and typically occur under unusual circumstances. One scenario involves narwhals becoming trapped in “sassats” or ice entrapments, where sudden changes in weather or ice conditions cause open water areas to freeze rapidly. When narwhals are confined to small breathing holes, they become more accessible to polar bears.
Polar bears have been observed waiting at these breathing holes for narwhals to surface, sometimes attempting to suffocate them or inflicting injuries. Documented instances include polar bears scavenging on narwhal carcasses found along shorelines or on ice, which provides significant nutritional benefit, particularly when seals are scarce. Although active predation on narwhals is less common than scavenging, successful attacks on juvenile narwhals have been reported. These events highlight polar bear adaptability, but remain rare compared to their consistent reliance on seals.