Chameleons change their skin colour in response to temperature, light, and mood.
Contrary to popular belief, chameleons don't change colour to blend in with their surroundings. A main reason chameleons change colour is so they can communicate with each other. Through colour changes, chameleons can express moods, attitudes, and the desire to mate. For example, a calm chameleon is often green, while an angry chameleon will most likely turn yellow. Another widespread belief is that chameleons can become any colour they want to.