Instant Camouflage

An octopus can change its color, texture, and even shape in under a second. The color comes from tiny pouches of pigment called chromatophores; squeeze them and a color shows, relax them and it hides. Reflective layers underneath scatter light to add shimmer and bright white.

Here is the puzzle. An octopus appears to be color-blind — its eyes carry just one kind of color sensor. Yet it matches the colors around it with eerie accuracy. The leading clue: its skin itself reacts to light, so the body may be reading the scene even when the eyes cannot.