How do octopuses change color?

Octopuses change color by tightening and loosening tiny muscles in their skin. Those muscles open and close pigment-filled cells called chromatophores, so patches of red, yellow, brown, and orange can appear almost instantly across the body.

Under those color cells, octopuses have shiny and pale layers that bounce and spread light, helping them look silvery, blue-green, or white. The strangest part is that many octopuses do this while seeing mostly light and dark, so their skin may help judge the scene.