Alright, so Ruth is a deer mouse (genus: peromyscus) and her cagemate Sandy (a fancy mouse, mus musculus) had to be euthanized today so I guess I need to get a new companion for Ruth.
A little about Ruth: She is very tiny, only weighs about 15-20 grams, fast, and not tame at all. Deer mice have a need for higher protein diets than fancy mice, but we can mostly deal with that if necessary.
I would sorta like to avoid the fancy mouse route just because of the high prevalence of tumors in female fancy mice, and would also sorta like to avoid a male fancy mouse because of their smell. I can deal with either if necessary, but I want to see if their are other options besides smelly (to me) male fancy mice, or tumor prone female fancy mice. A slightly longer life span would also be nice since Ruth will likely live for 4-6 more years and changing companions every year will be pretty rough if it comes to that. It would also be nice to find a type of mouse that matched her more closely in diet, but again that's not really necessary.
So, what type of mouse should I get to be Ruth's companion?