Camouflage Chemistry/Biology

After my presentation today, Anthony asked a very good question regarding the chemistry of camouflaging. It sparked my interest to look up the subject matter and write my final blog over it. I found a website that explained the science behind camouflaging very well, so I am just going to directly quote it.

'Chameleons change color by manipulating the chromatophores in their sub-dermal layer. Each chromatophore contains one pigment, and a sphincter muscle. When contracted, the pigment is squeezed up into a flat region above the chromatophore, showing that pigment. As you can imagine, this works much like an RGB display; an animal can have only a few pigments, and make many different colors by combining them selectively. Chameleons have four different layers to their skin, in order of increasing depth: the protective epidermis, the chromatophore layer (which contains red and yellow pigments), the melanophore layer which can display brown or black pigments or reflect blue, and the nether layer, which is white. Any given color morph of a species of chameleon only has a few different patterns and color combinations in its palette.

So say the chameleon is frightened by a Boomslang or a Shrike (both predators of chameleons), a combination of hormone action and nerve impulses will selectively expand and contract some chromatophores of the chameleon into either a camouflage pattern or a bright pattern which often means "I taste bad" or "I'm poisonous" in the animal world. These transitions can take as little as a few seconds, and a viewer will see a gradual shift from one color pattern to the other. '

http://everything2.com/node/1685107