Polar bears live in some of the harshest conditions on earth, shrugging off Arctic temperatures as low as -45°C. While the bears have many adaptations that allow them to thrive when the temperature plummets, scientists have been trying to understand how their fur manages to keep them warm in their environment.
Polar animals actively use the sunlight to maintain their temperature through their white fur. While it might be assumed that black fur would be better at absorbing heat, it turns out that the polar bears’ fur is extremely effective at transmitting solar radiation toward the bears’ skin.
“But the fur is only half the equation,” said the paper’s senior author, Trisha L. Andrew. “The other half is the polar bears’ black skin.”
Polar bear fur is essentially a natural fiberoptic, conducting sunlight down to the bears’ skin, which absorbs the light, heating the bear.
But the fur is also exceptionally good at preventing the now-warmed skin from radiating...