I could have posted this in health,, but its not really a health issue so heres my question.....

when we are tossing Merlins toys around for him,,, he will chatter his teeth while waiting for us to throw the toy for him,, its hilarious,,,, does anyone know why they do this or does anyones dogs do this besides mine?? you can actually hear them clatter too when he does it,,, too darned funny!