Originally Posted by TareG
I have 3 female mice housed together (at one point it was 6), and I have never had any aggression problems. They wrestle over food, however, lol, but they have never bitten each other. I would suggest keeping a really close eye on them for a while and try and see what exactly initiates the tail biting. Is it over food? Is it territorial over a certain toy or house, etc? If there's nothing you can change to make it stop I would suggest seperating them. Normally, mice are social and do not like to be alone, though, so I am very suprised. Especially considering the recent onset of this biting and their age!
Good luck, and keep us posted!
Thanks for your reply.
It doesn't seem to be over anything in particular. There are no new toys in their cage (new toilet roll tubes, but only to replace old ones which we do regularly).
They do argue over food sometimes - lots of squeaking but no contact.
The first time we actually saw it happen, they were sat apart in the cage, one at either side of their wheel. The submissive mouses tail was laid under the wheel. The dominant mouse just bit it and pulled on it. The mouse let out a horrible squealing noise and ran awaw into a corner with it's tail bleeding. It then vanished into the house and licked it's tail before coming back out and started chewing on some food.
Interestingly enough, some months ago, we noticed that the dominant mouse had a kink in the end of it's tail and a scab. We just though they had got into a fight and never though any more of it after we kew it was not ill. Maybe this has been going on before but in reverse!
I read online somewhere that mice sometimes tail-bite when deciding who is boss in the cage. But after this long together, you'd think they already knew who was boss! Maybe the submissive one tried to be more aggressive and the other has been putting it in it's place!