Read the passage and then answer the question.

Polar bears live in the Arctic near the North Pole. They have two layers of fur and plenty of fat to keep them warm. Their favourite food is the ringed seal, an animal that swims in the ocean beneath the ice. In winter, the seals cut breathing holes in the thick ice. Polar bears hunt the seals by waiting for them to come up through the holes for air. That’s when the seals are the most vulnerable. A polar bear may have to wait at a hole for many days. But if the bear is patient enough, it might end up with a tasty treat.