Polar bears are found in the tundra biome. The tundra is a cold and treeless biome characterized by low temperatures, short growing seasons, and a layer of permafrost. It is home to various species adapted to survive in extreme cold, including polar bears. These bears are well-suited for the tundra environment, with their thick fur and layer of blubber that helps them withstand the freezing temperatures. They rely on the tundra's unique ecosystem, which includes ice, snow, and marine mammals, for hunting and survival.