A subpopulation is a group of polar bears with a home range independent of but overlapping that of other polar bears. Polar bears inhabit Arctic sea ice, water, islands, and continental coastlines. It runs parallel to the polar basin coastline. Some polar bears spend part of the year on land. Polar bears in warmer climates may become stranded on land.
Most pregnant females spend the autumn and winter on land in maternity dens.
Polar bears travel throughout the year within individual home ranges. Home ranges tend to be larger than for other mammal species because sea ice habitat changes from season to season and year to year. Small home ranges can be found near Canadian Arctic islands. Large home ranges can be found in the Bering or Chukchi Seas. Polar bears don't mark or defend their home ranges.