Reptile & Amphibian Forums

I have a mouse that is one year old. Yesterday I got a new baby mouse. They are both females, and the cage is large, but my older one attacked the younger more than once. I put my younger one in a small clear container with food and water inside the cage, so they could see & sniff one another. Ofcourse it has only been a day, but if any one has any better ideas please help!

Having a mouse alone for a year is not healthy for mice.They are social animals and need others of their kind to remain both physiclaly and mentally healthy. Normally female mice are pretty easy to introduce to eachother, providing neither is near to giving birth or currently nursing young.

As your current mouse has been alone for the entire time you had her, it will take much longer to introduce her to a new mouse. Keep them separated like you have for a week or so, then introduce them both together in neutral territory (a play area or other similarly enclosed space that isn't one or the other's normal living area). Watch them interact and if things do get aggressive (it is normal for some chasing around and rough and tumble but if there is any serious biting or loud squeeks, separate immediately). Give them another week or a few days and try again on neutral territory. Eventually the adult female may grow to accept the younger female but she may never do so.

It may also be better to buy a third female mouse so your newest one won't be alone all the time, especially if your adult female refuses to accept her.
-----
PHLdyPayne

Thank you for your reply. I understand better now, it will help.