Actually, this was the first time I´ve ever seen them mount each other. I´m keeping an eye on Gavin, he seemed slightly off which may be the cause of all of this. He wasn´t his usually energetic self, so he may be going to see the vet soon.
Any ideas on what causes these periodic episodes? I know that the one before this was triggered by moving to a new cage, but I have no idea what set this one off.