How does an animal make bright white skin without white paint? Leucophores do it with tiny grains that bounce light everywhere.
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Some animals have skin cells that make the color white. They are called leucophores (say "LOO-ko-fors").
Cuttlefish and octopuses have them. A cuttlefish is a sea animal related to squid, with eight arms and two long tentacles. Some small fish have leucophores too, like the Japanese rice fish, also called the medaka.
Each leucophore is packed with lots of tiny grains, a bit like a little bag of glitter. Your own skin does not have these cells.
Sunlight looks white, but it is really all the colors of the rainbow mixed together. When light hits the tiny grains, it bounces off in every direction. All the colors bounce back together, so we see white.
White spots and stripes help these animals blend in with bright sand and rocks, or stand out when they want to be seen.
Scroll up to the 3D model and press Shine light. Then look at a pile of salt or sugar. Each grain is clear like glass, but the pile looks white because light bounces around all the grains!
Leucophores bounce back whatever light shines on them. Deep in blue ocean water, a cuttlefish’s white spots look a little blue, so they match the water around them.