How did the polar bear evolved?

Zoologists believe that the polar bear evolved from a species of brown bears in Siberia, making polar bears the eighth species of bears. With the shifting of polar ice caps and glaciers, the brown bear species native to that area was forced to adapt to the new environment, undergoing physical body changes to keep warm in the brutally cold weather. Their fur thickened and eventually turned white. Over time, the next few generations evolved with even thicker fur, a more rounded pointy face, larger teeth and claws, bigger feet with a patch on the bottom to help them keep their grip, while walking on the ice and sharper senses. Today, polar bears live in the Arctic, Alaska, Greenland, Canada and Norway. Their habitat is snow-covered mountains, mostly frozen bodies of water and where seals are found in abundance. Besides seals, polar bears eat walruses and even whales. The snow helps them blend into their environment for safety, even though man is their only predator.