Bearded Dragon Aggression

My friend's bearded dragon is becoming aggressive. The dragon was sexed as a female and my friend also sexed her as a female, but this dragon will puff our her beard and the beard gets really dark, actually black. She has bit a few times and broken skin. Today while I was visiting my friend (she got kittens!) she showed me her dragon's new attitude problem. I approached the tank and she was sitting on her rock. (its not a heat rock, don't worry) and she puffed up her beard at me. Apparently, she went crazy a few weeks ago during feeding time, attacking my friend when she went to put her back in the tank (she is fed outside her enclosure).

The dragon is in a very long 75g tank with heat lamp, several logs and rocks to climb on and hide in/behind. Her substrate is tile. She is fed a diet of crickets and veggies/greens.

Any ideas?

Is the dragon an adult? It's common for them to go through a pissy phase while maturing, but they grow out of it

I'm not sure of her exact age but I think she is an adult. I can find out her age tomorrow.

Adolescence. :rolleyes:

Could you explain a bit about the lamp? What brand? Type? Wattage? When was it last replaced? What are the temps in the cage?