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
Underwater camouflage bottom-living fish such as the flounder can hide themselves effectively against a variety of backgrounds. Many cephalopods including octopus, cuttlefish, and squid similarly use colour change, in their case both for camouflage and signalling. For example, the big blue octopus, "Octopus cyanea", hunts during the day, and can match itself to the colours and textures of its surroundings, both to avoid predators and to enable it to approach prey. It can perfectly resemble a rock or a coral it is hiding beside. When necessary, in order to scare away a potential predator, it can display markings which resemble eyes. Like