Polar bears are actually transparent...?

Polar bear fur is indeed transparent and colorless. They appear white due to the physics of light refraction, and the skin underneath their fur is actually black. How Fur Appears White and Skin Absorbs Heat Hollow Structure: Polar bear hairs (guard hairs) contain no pigment and have a transparent, hollow shaft. Light Refraction and Scattering: When sunlight hits these hollow, transparent hairs, light repeatedly reflects and scatters between the hair's interior and the air pockets. This process reflects all wavelengths of light, which our eyes perceive as white, providing excellent camouflage in snowy environments. Black Skin for Efficient Heat Absorption: The skin beneath the fur is black, maximizing the absorption of solar heat conducted through the transparent hairs. Combined with up to 10 cm of subcutaneous fat and the insulating air within the hollow fur layer, this helps them retain body heat in extreme cold. Sometimes, in zoos, if microscopic algae grow within the hollow structure of polar bear fur, the hairs might temporarily appear greenish or yellowish. No wonder the polar bears at the zoo look kinda dirty @@