According to Polar Bears International, polar bears have adapted to challenges facing the species since it evolved and are currently in the process of adapting to new challenges, such as climate change. According to Defenders of Wildlife, polar bears have thick fur and blubber that adapt them to their environment by keeping them warm and buoyant. They also evolved large feet that help them to swim.
Polar Bears International, a non-profit organization dedicated to the species' survival, notes that polar bears diverged from their common ancestor with brown bears at least 4 million years ago. At this time, they began to evolve the traits that helped them adapt to a life spent in the icy polar regions. Additionally, because they capture most of their food in the ocean, they acquired important swimming adaptations, such as a streamlined face, states Defenders of Wildlife.
World Wildlife Fund reports that polar bears live across a vast range that encircles the North Pole. Scientists split the bears into 19 different subpopulations. Each population must adapt to the unique challenges it faces; some subpopulations may not be able to adapt to their changing habitat. The World Wildlife Fund holds that five of the 19 subpopulations are currently in decline.