Polar bears aren't actually white. Their color is determined by the lighting and climate of their surroundings. Following is a transcript of the video.
Polar bears aren't actually white.Turns out, they can come in all sorts of colors: yellow, gray, orange, and even green. That's because polar bear fur is transparent and hollow.When light strikes the outer fur some of it is absorbed while the rest is scattered away.
The result? The fur can appear as different colors under different lighting. Normally, polar bears look white. That's because their fur is scattering sunlight, which is also white. But on a cloudy day, the bears can look slightly gray. At sunset, they can appear reddish-orange. But lighting is only half the story.
Polar bears in zoos have been known to turn green. Concrete floors in their pens scrape against the fur. The abrasions form tiny holes in their hairs, opening a gateway for algae that can live and breed inside. In the Arctic, temperatures are too cold for these algae. But wild polar bear fur can still change color to yellow, thanks to oils from their prey that stain the fur.
Perhaps the most surprising thing about polar bears? Underneath all that hair, polar bear skin is actually black. The black skin readily absorbs sunlight to keep the bear warm. Polar bears aren't just the ambassadors of the North Pole. They're masters at manipulating color to survive.