Females assess the scent marks of males and interestingly base their mating preferences on a male's phenotypic quality as well his territory quality. For example, females prefer males who can successfully defend their territories against rivals . They prefer the odor of dominant to subordinate males , and they can even discriminate the sons of dominant males from the sons of subordinate males by their odor . Females can recognize siblings, even unfamiliar ones, and prefer unrelated males to siblings . Female house mice often nest communally and nurse each other's pups, like lions and a few other mammals.
Cooperative breeding is a strategy to reduce pup loss from infanticide .
Familiarity among females increases the reproductive success of communally nesting females, especially if the females are closely related . Females tend to nest with their sisters in the wild , and they tend to communally nest with MHC-similar females, supporting the idea that the MHC provides a kin recognition system . Selander, R. K. Behavior and genetic variation in natural populations. Dewsbury, D. Copulatory behavior as courtship communication. The role of breeding structure in evolutionary processes of Mus musculs populations.