The polar bears white fur is not made of fiber optics, but instead they are hollow. To keep warm, a polar bear has two types of fur; a top layer and an under layer. The top layer is made up of long oily hairs which act like a winter jacket does; it is the protective layer which keeps the polar bear warm and dry. When a polar bear goes for a swim, the top layer keeps the under layer from getting wet. When they are done, they can shake the water off, like a dog. The under layer is a soft layer of fur that acts like a sweater does. It is thick and woolly, and keeps the bear warm. All the little spaces between the hairs are just like the little spaces between the threads of a sweater, it holds on to warm air, which keeps the polar bear warm. Under those layers is blubber. Each hair also has little spaces to hold more air, which makes polar bear hair very good when keeping polar bears warm. Theses hairs also help them float. Their white fur is used as camouflage which prevents a predators attack! They also have strong and wide paws and nose powerful enough to detect prey that is miles away. This is basically how a polar bear survives. I hope I answered your question! :D
