How do chameleons change their colour?

Chameleons change their colour by manipulating specialised skin cells called chromatophores and iridophores. Chromatophores contain pigments, while iridophores reflect light using nanocrystals. By adjusting the spacing of these crystals, chameleons can alter the way light interacts with their skin, creating different colours. This ability is used for camouflage, communication, and thermoregulation. For example, a chameleon might turn darker to absorb more heat or display bright colours to signal dominance or attract a mate.