I got my dragon about two weeks ago, he is roughly four months old and 9 inches long. I saw him head bob for the first time today. I was feeding him and he just started doing it lol. He also did it to the cat that was annoying him, it likes to stare at his cage. He also puffs out at me and opens his mouth sometimes but calms down when I pet him, mist him, or pick him up. I think he does this because I have to reach down to get him and he doesn't like things above him really he gets spooked. He will run around his cage very fast away from me sometimes but once I get him he just sits there. I til he decides he wants to explore and jumps and runs away and tries to leap off the bed, he has done it twice it scares me because I don't want him to get hurt so I stop him most of the time unless he squeaks by. He also puffs out and opens up his mouth at my cat when he looks her in the eye.