According to a new report recently in the journal Nature Communications, chameleons are able to rapidly change their color by adjusting a layer of unique cells nestled in their skin. Chameleons use structural changes that affect how light reflects off of their skin.
A group of researchers observed five adult males, four adult females and four young Madagascar panther chameleons or Furcifer paradalis in order to investigate this ability. The investigative group discovered that the lizards had two “superposed thick layers of iridophore cells. (Iridophore cells are iridescent and contain pigment that reflects light.)
These cells have nanocrystals of different shapes, sizes and organizations, which are essential to the chameleons’ ability to change color. By relaxing or arousing their skin, chameleons change the structural arrangement of the upper cell layer. This leads to the color change.
For example, a chameleon could be relaxed while napping on a branch. He could be in an excited state when he spots a rival.
Michel Milinkovitch, a professor of genetics and evolution at the University of Geneva in Switzerland and senior study author said: “When the skin is in the relaxed state, the nanocrystals in the iridophore cells are very close to each other — hence, the cells specifically reflect short wavelengths, such as blue.”
He also said that when a chameleon’s skin becomes aroused, the distance between nanocrystals increases. Every single iridophore cell reflects longer wavelengths, like red orange or yellow. The chameleons’ skin contains yellow pigments as well which further aids in the process.
Additionally, the team of researchers learned there is a thicker and deeper layer of skin cells that specifically reflect a significant quantity of “near-infrared sunlight.” Although these particular cells do not actually cause any change in color, the scientists believe that they do assist the chameleons stay cool by reflecting heat.
How Do Chameleons Change Color?