Mice are very sociable animals who, in most cases, enjoy the companionship of other mice. They will spend hours grooming one another and exploring their enclosure together.
Although in some cases males can live together, many pairs or groups of males often start to fight quite aggressively regardless of the space they live in. In most cases, it’s best to house male mice as singles. Females can happily live together in pairs or small groups. They’ll also accept newcomers if the introduction is done correctly and carefully.
Always introduce mice on neutral territory such as a cage that has been thoroughly cleaned and contains neither mouse’s scent. This should then be set up with lots of interesting places and objects to explore.
A few hidey-holes will offer welcome refuge, but make sure that you can intervene and remove the mice if a fight breaks out. Once the cage is set up, the mice can be placed in at the same time.
Usually they’ll just walk straight past each other and explore their new surroundings. It can take between one hour to two days for the mice to develop a bond. You should be able to tell if the mix is likely to work within the first hour.
Even if the signs are encouraging, keep a close eye on the mice until they have settled.
If this kind of behaviour persists for more than an hour, separate the mice. Unfortunately, this particular mix is not likely to work.
However, follow all the steps listed above and there’s an excellent chance your mice will bond and become lifelong friends. Good luck.