Explain how the physical appearance of polar bears distinguishes their species from other bears and ...

Many of the differences in physical appearance between polar bears and other bears can be linked to the polar bears' adaptations to life in an extremely cold environment and to the fact that they hunt on sea ice. Individual hairs of polar bears' outer fur layer are hollow, providing both waterproofing and insulation against the cold. The fur, which is actually transparent, appears white against their underlying black skin, providing camouflage (black or brown bears would stand out in the ice and snow-dominated landscape). Polar bears have a thick layer of blubber that contributes to their ability to retain heat. On the pads of their paws are small bumps which, along with their thick, strong claws, provide traction on the ice. Their powerful paws are good for swimming.