Bearded seals have two main predators, polar bears and killer whales. Polar bears hunt seals by waiting near a breathing hole for their prey to surface. However, breathing holes of bearded seals usually form domes or caps of ice that they must dig through to reach the surface. This may serve as a defensive strategy, obscuring breathing hole positions and making them more difficult for polar bears to locate. Killer whales do not actively hunt bearded seals, but eat them opportunistically. Although rarely observed, pups of bearded seals are occasionally eaten by walruses. Bearded seals are also taken by humans through subsistence fishing by Native Americans in Canada and Alaska.