How does a chameleon change its colour?

The ability to change its colour is one of the foremost characteristic features of chameleon. This colour change is due certain properties of special, pigment containing cells called chromatophore cells in the three skin layers found below the outer skin layers.

The cells of the uppermost layer next to superficial transparent skin are called xanthophores .These cells are yellow pigmented cells. The granules of pigment within these chromatophore cells can selectively reflect and absorb certain wavelengths of light.

These cells are responsible for the yellow and  red pigmentations. The next is a light scattering layer and is called iridophores. The platelets here can reflect blue lights. The cell of the deepest layer are called melanophores, which contain  black pigments.

The chameleons hormones cause the granules of melanin  present in these cells to be either distributed widely throughout the cell or to  be gathered together into one small lump near the center of the cell. The way the melanin granules are dispersed can change the optical  properties of cells.

            When the melanin granules are completely contracted, we  see primarily the yellow pigment in the chameleons skin. When there is no Tyndall effect the blue light scattered by from cells  of the scattering layer is mixed red, orange yellow and green wavelengths of  the spectrum reflected by the melanophores of the deep layer.

        The chameleons skin looks tan, green, or dark  green, depending on how widely dispersed the melanin granules are. When  the melanin granules are fully dispersed, the animal's skin looks quite dark,  sometimes even black. When the melanin granules are partially dispersed, the melanophores  absorb red, orange, red and green wavelength, so that the blue scattered light  becomes more noticeable.

 

 

       

                   For video explanation click this link for easy understanding…..