Polar bears are only found in the Arctic. The most important habitats for polar bears are the edges of pack ice where currents and wind interact, forming a continually melting and refreezing matrix of ice patches and leads (open spaces in the ocean between sea ice). These are the areas of where polar bears can find the greatest number of seals. As the sea ice advances and retreats each season, individual polar bears may travel thousands of miles per year to find food. Polar bears are distributed throughout the Arctic region in 19 subpopulations, including Alaska, Canada, Russia, Greenland and Norway.