What color is a polar bear's skin?

A polar bear's skin is actually black. It's black so it can soak up as much of the sun's rays as possible. Polar bears have almost transparent fur over black skin. Reflection of the sunlight from the densely packed transparent hairs makes polar bears seem to be white. The bears' black skin absorbs heat from the sun. The seemingly-transparent fur is made up of hollow hairs called guard hairs. These air-filled guard hairs help transmit heat from the sunlight to the polar bear's black skin as a solar heat collector. In turn, the reflection stops the heat being lost from their black skin.

The polar bear's fur seems colourless and for many years, scientists worked on the theory that the individual hairs act as fiber optics bringing sunlight directly to the skin. This has recently been proven to be incorrect, and the hairs are not truly transparent, but contain keratin. Viewed side-on, the hairs appear colourless; viewed lengthwise (as if one was looking down a telescope) the hairs no longer appear transparent.

The Polar bear can swim in ice laden sea water quite comfortably. It is more in danger of hyperthermia (over-heating) then hypothermia (freezing).

First answer by Sweetlove1985. Last edit by On the Wallaby. Contributor trust: 1094 [recommend contributor]. Question popularity: 4 [recommend question].