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
Underwater camouflage one of these methods to camouflage themselves. Camouflage in relatively shallow waters is more like terrestrial camouflage, where additional methods are used by animals in many different groups. These methods of camouflage are described in turn below. Transparency is common, even dominant, in animals of the open sea, especially those that live in relatively shallow waters. It is found in plankton of many species, as well as larger animals such as jellyfish, salps (floating tunicates), and comb jellies. Many marine animals that float near the surface are highly transparent, giving them almost perfect camouflage. However, transparency is difficult for bodies