Polar bears live in the Arctic. The Arctic continent is a huge piece of ice on the earth. Polar bear is a kind of bear in Ursidae. It is the largest land carnivore in the world. It is also called white bear. The polar bear"s big paw enables it to use the front paw as a "paddle" to swim in the water, while the wide back paw is used to walk on the ice and in the snow; the sense of smell is extremely sensitive, which can capture the smell of a kilometer around or one meter under the ice and snow.