Polar bears hunt their main prey, ringed seals, by waiting on the ice near breathing holes that the seals use for oxygen. Once the seals surface, the polar bears attack. Polar bears are creatures of opportunity, hunting and feeding on any convenient wildlife, including whales trapped in ice.
Ringed seals cut holes in ice before the onset of winter using their claws. Polar bears sniff out these holes and lie in wait. Because there are dozens of these holes, it can take hours, even days, for the seals to surface at a particular one. Polar bears also stalk seals lying on the ice. The polar bears crawl toward the seals, trying to get as close as possible before attacking. Usually the bears pounce from 20 feet away before the seals can escape back into the ocean.
Polar bears also hunt other marine life if they can find it, including walruses and even whales. Bears wait until a whale becomes trapped in pack ice before attacking or feeding on the whales. They also eat whale carcasses that wash ashore.
Polar bears also hunt caribou, geese and even bird eggs. They feed on vegetation when desperate, though this alternative food source doesn't provide the bears with the calories necessary to sustain them.