In octopuses, more of it “turns on” the greens and blues; less creates pinks and golds. The topmost layer of the octopus’s skin contains chromatophores, tiny sacks of yellow, red, brown, and black pigment, each in an elastic container that can be opened or closed to reveal more or less color. Camouflaging the eye alone—with a variety of patterns including a bar, a bandit’s mask, and a starburst pattern—can involve as many as 5 million chromatophores. Each chromatophore is regulated via an array of nerves and muscles, all under the octopus’s voluntary control.
