Maternal Aggression and Infanticide in the House Mouse: Consequences on the Social Dynamics.

The ethological literature contains many, generally anecdotal, accounts of attacks by breeding vertebrates on other species or strange conspecifics 1,2 . Since the female in many species, is the more involved in parental care, such behaviour has often been described as “maternal aggression” 3 . It is easy to understand the reasons for parental attack on potential predators but what is the function of such attacks on conspecifics? Infanticide of unrelated young occurs commonly in many animals and, in certain situations, can be interpreted as an adaptive reproductive strategy 4 . This kind of infanticide is certainly found in rodents 5,6,7 and one may speculate that intraspecific attack protects neonates from infanticide 8,7 . Maternal aggression and infanticide by strange conspecifics (especially males) are well-documented in House mice (both Mus musculus and Mus domesticus) 10 .