They are mostly carnivorous. Polar bears are apex predators. They eat mostly seals and fish. They also eat sea lions, walruses, reindeer, arctic hares, penguins, seagulls, small whales, lemmings, crabs and carrion. When polar bears hunt, they often wait at holes in the ice, where the seals come up to breathe. They can live off of one seal for many days, but it will make them hungry if they do.