Many chameleons have the remarkable ability to exhibit complex and rapid color changes during social interactions. Biologists have now unveiled the mechanisms that regulate this phenomenon. They have demonstrated that the changes take place via the active tuning of a lattice of nanocrystals present in a superficial layer of dermal cells called iridophores. The researchers also reveal the existence of a deeper population of iridophores with larger and less ordered crystals that reflect the infrared light. The organisation of iridophores into two superimposed layers constitutes an evolutionary novelty and it allows the chameleons to rapidly shift between efficient camouflage and spectacular display, while providing passive thermal protection.
Source: Université de Genève. (2015, March 10). The chameleon reorganizes its nanocrystals to change colors.