they do it sometimes when they are pissed but it could mean they are too hot also. If he does it all the time it could possibly be early signs of a respiratory infection or something.
Hello, It will help the experienced keeper if you could fill out the questionnaire on the link below. Just copy and paste in your reply and then fill your answers in with as much deteil as possible. It would also help if you could post some pics of enclosure and of your Chameleon. https://www.chameleonforums.com/how-ask-help-66/