Camouflage Animal coloration

one of pioneers of research animal coloration, edward bagnall poulton classified forms of protective coloration, in way still helpful. described: protective resemblance; aggressive resemblance; adventitious protection; , variable protective resemblance. these covered in turn below.

a camouflaged orange oak leaf butterfly, kallima inachus (centre) displays protective resemblance

protective resemblance used prey avoid predation. includes special protective resemblance, called mimesis, whole animal looks other object, example when caterpillar resembles twig or bird dropping. in general protective resemblance, called crypsis, animal s texture blends background, example when moth s colour , pattern blend in tree bark.

a flower mantis, hymenopus coronatus, displays special aggressive resemblance

aggressive resemblance used predators or parasites. in special aggressive resemblance, animal looks else, luring prey or host approach, example when flower mantis resembles particular kind of flower, such orchid. in general aggressive resemblance, predator or parasite blends in background, example when leopard hard see in long grass.

for adventitious protection, animal uses materials such twigs, sand, or pieces of shell conceal outline, example when caddis fly larva builds decorated case, or when decorator crab decorates seaweed, sponges , stones.

in variable protective resemblance, animal such chameleon, flatfish, squid or octopus changes skin pattern , colour using special chromatophore cells resemble whatever background resting on (as signalling).

the main mechanisms create resemblances described poulton – whether in nature or in military applications – crypsis, blending background become hard see (this covers both special , general resemblance); disruptive patterning, using colour , pattern break animal s outline, relates general resemblance; mimesis, resembling other objects of no special interest observer, relates special resemblance; countershading, using graded colour create illusion of flatness, relates general resemblance; , counterillumination, producing light match background, notably in species of squid.

countershading first described american artist abbott handerson thayer, pioneer in theory of animal coloration. thayer observed whereas painter takes flat canvas , uses coloured paint create illusion of solidity painting in shadows, animals such deer darkest on backs, becoming lighter towards belly, creating (as zoologist hugh cott observed) illusion of flatness, , against matching background, of invisibility. thayer s observation animals painted nature, darkest on parts tend lighted sky s light, , vice versa called thayer s law.