How do chameleons change colour?

Chameleons change colour by manipulating specialised skin cells called chromatophores and iridophores. Chromatophores contain different pigments, while iridophores reflect light. By altering the spacing of nanocrystals in the iridophores, chameleons can change the way light is reflected off their skin, creating a variety of colours. This ability helps them communicate, regulate body temperature, and blend into their environment for camouflage. The process is controlled by the nervous system and hormones, enabling rapid changes in response to external stimuli.