Chameleons are almost totally deaf but they do pick up on vibrations. Some chameleons, eg Veiled and Flap-neck vibrate in your hand if you pick them up. This is them trying to communicate with us because in the wild two chameleons sharing a branch will communicate with each other by vibrating(they feel the vibrations travelling along the branch). They are sensitive to vibration and will become stressed near activity such as someone playing the drums.
That is so cool!! I've felt that when holding Herbie(veiled) it was kind of like grunting but it made more of a vibration than a sound. He was half asleep in my hand and I was putting medicine on his cut,
How did you here about that? It's good to have you on Cham Girl
I noticed that my Veiled chameleon used to vibrate all the time in my hand and I couldn't find out why. No-one seemed to know, then I read about it one day in an article and that answered my question. It is a little known fact that Flap-necks do it too. My own Flap-neck used to vibrate in my hand and as only Veiled are really known to do it I used to doubt myself. Then I read somewhere on the internet that Flap-necks do it too. There are supposed to be other species that vibrate too but I've never owned any of those to confirm it.
Below is a small extract taken from Chameleons online E-zine May 2003:-
In a study the low frequency sounds of Ch. (Ch.) calyptratus were recorded using PCB accelerometers and canary software. They proposed that this vibration was a form of communication whereby the vibrations were transmitted through the branches of trees.
EDIT: Just found this so I copied and pasted it from Adchams Veiled chameleon profile:-
A more recent (unpublished) speculation is that the casque might serve to amplify the low frequency "buzzing" used by veileds to communicate.
They also communicate by their colouration changes. For example, a female chameleon can easily indicate to a male whether she is receptive to mating or not. When she is pregnant, she displays her gravid colouration, again to tell the males to leave her alone. Chameleons can also display angry colouration, ill colouration, excited and stress colouration etc. All of these give out clear signs to the other chameleons in the area.