A bearded dragon bobs its head when trying to exert dominance over another bearded dragon. Bobbing the head also signals that a male dragon wishes to mate with a female.
Head-bobbing is typically seen in older bearded dragons that project dominance over younger dragons.
This signal is also directed towards smaller bearded dragons and females. To counteract the gesture, a subordinate dragon waves one of the forelimbs as a sign of submission, and females do the same to steer clear of aggressive males. Head-bobbing also occurs when a dragon encounters hostility or issues a challenge to another dragon. To mark the challenge, the head gesture is accompanied with flattening the body and puffing the throat. A dragon may also have a darkened beard when exhibiting dominant behavior or feeling threatened.