Chromatophores are color-changing cells that allow some animals, such as cephalopods, a class of molluscs that includes octopuses, squids and cuttlefish, to blend in with their surrounding environments. Chromatophores are also used to communicate different messages to potential mates, rivals and predators.
Chromatophores are cells that comprise pigment-filled sacs found just below the skin of cephalopods with the exception of the chambered nautilus, which lacks this biological adaptation. These cells expand and contract to exhibit different pigments, which allows the animal to change the color of its body to resemble its environment for defense, hunting and mating purposes.
Squids employ chromatophores to virtually disappear at will in the presence of predators and rivals and to entice prey and potential mates. The number of individual cells found on a squid's body determines the complexity of the pattern produced.
In the dark depths of the ocean, this ability to change color is bolstered by the presence of photophores, which are light-emitting cells found across the bodies of many species of squid. Photophores permit bioluminescence, whereby light-producing organs emit illumination from across the body of the animal. These light producers range from a simple collection of cells to a complex arrangement of lenses, filters, shutters and reflectors.