Maternal aggression in response to the risk of infanticide by male mice, Mus domesticus

This study investigated whether maternally aggressive female mice can discriminate between infanticidal and non-infanticidal males. The effect of maternal experience and of the presence or absence of pups on this discrimination were also tested, in a factorial design. Parental experience of the mothers did not influence their responses or those of the males. When pups were present, but not when they were absent, females were more likely to attack infanticidal males than non-infanticidal males. Females were more likely to attack infanticidal males in the presence of pups than in the absence of pups but the reverse occurred with non-infanticidal males. When pups were present, females were more likely to adopt a defensive posture to non-infanticidal males than to infanticidal males. Infanticidal males were more likely to attack the female in the absence of pups than in their presence and this may be because females were less likely to attack them in the former situation. Female attack was initiated by the presence of the male not by his action towards the pups. These data indicate that females discriminate between males of the same reproductive status but of different infanticidal tendencies and respond according to the risk to their young.