Are polar bears white?
Polar bears look white, but their fur is actually made of transparent, hollow-looking hairs that scatter light. Their skin underneath is black.
Each hair in a polar bear's outer coat is colorless and has a hollow-looking core. When light hits the hairs, it is scattered, making the fur appear white, much like snow and ice appear white even though water is clear. The fur can look yellowish from oils and food stains, especially in summer.
Under the fur, polar bears have black skin, which can be seen on their nose, lips and footpads. Scientists once thought the hollow hairs acted like fiber-optic cables carrying sunlight to the skin, but later studies showed this is not true. The black skin may still help absorb some heat.
Green polar bears?
In some zoos in warm climates, polar bears have turned slightly green. Tiny algae grew inside the hollow parts of their hairs. The bears were healthy, and the color disappeared after the fur was treated.
Did You Know?
The white color helps polar bears blend in with snow and ice while sneaking up on seals.