How do squid and octopuses change color?

A number of cephalopods--the group of animals that includes octopuses, squid and cuttlefish--are skilled in the art of color change, which can be used for camouflage or to startle and warn potential predators in their undersea realm. Many of these creatures have special pigment cells called chromatophores in their skin. By controlling the size of the cells they can vary their color and even create changing patterns. Chromatophores are connected to the nervous system, and their size is determined by muscular contractions. The cephalopods also have extremely well developed eyes, which are believed to detect both the color and intensity of light. Using their excellent eyesight and chromatophores, cephalopods camouflage themselves by creating color patterns that closely match the underlying seafloor. In squid, color changes also occur when the animal is disturbed or feels threatened.

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