Beneath their iconic white fur, polar bears hide a surprising secret: their skin is completely black.
This dark pigmentation is a crucial thermal adaptation for survival in the Arctic. Black skin efficiently absorbs any solar radiation that manages to penetrate through their dense white fur.
A polar bear's white fur is not actually white, but translucent and hollow. Each individual hair is transparent and reflects light, creating the white appearance we know. This hollow structure also provides excellent thermal insulation.
The combination of heat-absorbing black skin beneath translucent hollow hairs creates a perfect thermal system: the black skin captures and retains solar heat, while the hollow fur acts as an insulating layer that prevents the loss of body heat. This ingenious adaptation allows them to maintain a stable body temperature in temperatures as low as -40°C.
Source: Arctic Biology Studies
