Polar bears often sleep seven to eight hours at a stretch and they also take naps!
It was once thought that polar bear hair acted as a fiber-optic tubes that transmitted ultraviolet light to the black skin in order to capture heat energy from the sun. This theory was tested and disproved in 1988 by physicist Daniel W. Koon. Instead, he found that the keratin protein in the hair actually absorbs much of the light before it reaches the skin.
[Photo by Copanda V.]
Not long until polar bear season begins!