Male Behavior Males establish dominance and territorial status by severe aggression . Our behavioral observations and genetic data both indicate that territorial males obtain nearly all matings, with subordinates only occasionally successfully mating. When fighting over territories, larger males have an advantage over smaller males , residents have an advantage over non-residents , and unparasitzed males have an advantage over parasitized males . Once males become territorial they patrol their territory performing tail-rattling displays and chasing away other males. They cover their territory with small scent marks of urine, whereas subordinate males deposit their urine in small puddles in the corner .
Males fight over real-estate because females prefer males with high quality territories .
Female Behavior Female mice prefer to nest in complex environments, with plenty of hiding places. Not surprisingly, they have strong preferences for males who occupy high quality territories . 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 .