Polar bears are large white furry sea mammals. They hunt their food of seals from the edge of sea ice, often living off fat reserves when no ice is present. Because of their dependence on the ice, polar bears are labeled as marine mammals. Because of habitat loss caused by climate change, the polar bear are classified as a vulnerable species, and at least three of the nineteen polar bear subpopulations are currently in decline. However, at least two of the nineteen subpopulations are currently increasing, while another six are considered stable.