trouble adding new mouse

Question
Hello. I had a 9 mth white mouse.Since i thought she would be lonely, I bought a new 1 month old female mouse for her.But though its been one month since then, she refuses to allow the small mouse in her cage and tries to bite her.How can I help them be friends ?

Answer
Dear Kusha,

Although sometimes a mouse is just too aggressive to live with another mouse, there is something you can try.  Leave the two mice separate for two weeks, during which time you don't clean the new mouse's cage. Then introduce the older mouse to the dirty cage.  Then let them do their thing-- unless there is blood. Chasing and squeaking is normal, even for a few weeks. As long as they sleep in the nest together, and the younger mouse still has access to food and water and doesn't appear depressed, they are fine.  If I am around for the chasing I occasionally like to take one or both mice out and hold them, to give the chased mouse a break.

If it just doesn't work out, then your original mouse is too aggressive to have a companion.  This is too bad, since mice are sociable creatures.  Keep the cages next to each other, since the mice do communicate all the time in squeaks we can't hear.  You can get a friend for the second mouse.  A mouse that lives alone needs a lot more people attention. You can probably hold them at the same time, though.  

I wish them the best of luck.  

squeaks,

Natasha