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
Snow camouflage advised either all-white using zinc white or titanium white paint for level, open country, or disruptive two-colour winter camouflage for areas with more variety including "forests, underbrush, small settlements, thawed patches of earth". The two colours could be achieved either by leaving around a quarter to a third of the vehicle's summer camouflage uncovered, or by repainting the whole vehicle in white with dark gray or gray-brown spots. Units were advised not to paint all their vehicles identically, but to have some tanks all white, some in white with green stripes, and some in white and gray or gray-brown. Winter