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
Dazzle camouflage was heading and where to aim. However, the ships painted in dazzle were larger than the uncamouflaged ships, 38% of them being over 5000 tons compared to only 13% of uncamouflaged ships, making comparisons unreliable. With hindsight, too many factors (choice of colour scheme; size and speed of ships; tactics used) had been varied for it to be possible to determine which factors were significant or which schemes worked best. Thayer did carry out an experiment on dazzle camouflage, but it failed to show any reliable advantage over plain paintwork. The American data were analysed by Harold Van Buskirk in