Active camouflage the surface, so when marine animals are seen from below, they appear darker than the background. Some species of cephalopod, such as the eye-flash squid and the firefly squid, produce light in photophores on their undersides to match the background. Bioluminescence is common among marine animals, so counterillumination may be widespread, though light has other functions, including attracting prey and signalling. Color change permits camouflage against different backgrounds. Many cephalopods including octopuses, cuttlefish, and squids, and some terrestrial amphibians and reptiles including chameleons and anoles can rapidly change color and pattern, though the major reasons for this include signalling, not
Camouflage matching of background colour and pattern, and disruption of outlines. Counter-illumination means producing light to match a background that is brighter than an animal's body or military vehicle; it is a form of active camouflage. It is notably used by some species of squid, such as the firefly squid and the midwater squid. The latter has light-producing organs (photophores) scattered all over its underside; these create a sparkling glow that prevents the animal from appearing as a dark shape when seen from below. Counterillumination camouflage is the likely function of the bioluminescence of many marine organisms, though light is also