Chameleon turquoise, and purple. Chameleon skin has a superficial layer which contains pigments, and under the layer are cells with guanine crystals. Chameleons change colour by changing the space between the guanine crystals, which changes the wavelength of light reflected off the crystals which changes the colour of the skin. Colour change in chameleons has functions in camouflage, but most commonly in social signaling and in reactions to temperature and other conditions. The relative importance of these functions varies with the circumstances, as well as the species. Colour change signals a chameleon's physiological condition and intentions to other chameleons. Chameleons tend
Military camouflage Military camouflage Military camouflage is the use of camouflage by a military force to protect personnel and equipment from observation by enemy forces. In practice, this means applying colour and materials to military equipment of all kinds, including vehicles, ships, aircraft, gun positions and battledress, either to conceal it from observation (crypsis), or to make it appear as something else (mimicry). The French slang word "camouflage" came into common English usage during World War I when the concept of visual deception developed into an essential part of modern military tactics. In that war, long-range artillery and observation from the air