I've had two gliders for a couple of years and they seem to get along very well. In the past 2 days though my female is missing a chunk of hair on the back of her neck, exposing red skin below. She also seems to have a small amount of hair missing from both cheeks. Do you think my male glider is doing this to her when I'm not around? Or could she be rubbing on something somehow?

is your male glider neutered? The patch of hair on neck sounds almost like a mating wound....

Maybe over grooming? What diet do you feed? Do they get alot of play time with you?

The male bites into the female's neck when they mate. This can happen whether or not he's neutered, but is less likely if he is. That's just how they do, they bite into her neck. It's usually fine but sometimes causes wounds. I would personally separate him if possible to let it heal, if it's an open would or may have been I would put a small amount of neosporin on it to lessen the chance of infection. If this happens again and your male is not neutered you may want to get him neutered to lessen his aggression levels, mating wounds can be quite bad. It's not so common but if he digs his teeth into her flesh then clearly things could go badly. Good luck.

Male is neutered but still marks her a lot by rubbing the top of his head on her. Diet is HPW and many fruits and veggies, and I play with them every day. After my male was neutered last year he became very aggressive to everyone and I had to really work with him to make him calm like he finally is now. But maybe she was in heat and he was trying to mate aggressively. I will keep a close eye on them but the wound is healing a lot so whatever it is seemed to stop. Weird. I hope I don't have to separate them every so often because of this.