Female mice bullying each other?
Hi. I have two female mice living in a 10-gallon tank together, I've had them for a couple of months (adopted them in December from a small pet store). I didn't notice until recently, Maybe they just started, But lately there has been squeaking noises coming from inside the tank. I run over and check on them, But by the time I get there whatever they are doing they've stopped. I've never seen them be aggressive with each other, I've tamed them and I always handle them together, They sometimes groom each other but it's mutual and neither looks more of an alpha than the other when they do. They both have access to clean water and food constantly, They are about the same size, And they have 3 hides at the moment (it gets changed around every week when I clean their cage, But they always have at least 2 hides, one for each).
Are my mice bullying each other? Or is the squeaking them just communicating or...? I don't have the money or space to have two separate cages for them both, And I can't give one up. I also heard somewhere that you should have at least three together because their hierarchy will be unbalanced or something? I'd like to get a third mouse but I don't know when or if I'll be allowed.
Please help! Thanks for any info or suggestions. I don't want my babies being mean to one another.