The polar bear is a large bear species native to Arctic regions. It evolved from brown bear ancestors around 200,000 years ago. Polar bears are well adapted to survive in Arctic conditions, with thick fur, fat layers, and large paws. They primarily hunt seals from the sea ice. There are estimated to be 20,000 to 25,000 polar bears total, found throughout the Arctic in Russia, Alaska, Canada, Greenland, and Norway. However, their sea ice habitat is decreasing due to climate change, which poses the greatest threat to polar bear survival.