Maternal behaviour in Mus musculus sp.: An ethological review

In this paper, we review the scientific literature on maternal behaviour in commensal house mice and laboratory mice. Similar to other altricial species, female mice prepare a nest before parturition. Once the pups are born, nursing is the main part of maternal behaviour, and pups are weaned through a gradual non-aggressive process after about 3 weeks. Mice are social and both males and females show parental behaviour. Female mice giving birth at about the same time form communal nests, where pups are also communally nursed, a phenomenon that may confer benefit in inclusive fitness. However, social living may also be risky with conspecifics being the main predators of pups. A distinct aggressive behaviour pattern shown by pregnant and lactating female is thought to protect nest and pups against such attacks. Maternal aggression is influenced by the presence of pups and by litter size and composition. Communication through external stimuli from the pups contributes to maintaining maternal behaviour, thereby influencing pup growth. Handling of infants and pre- and peri-natal stress affects maternal behaviour. When resources are limited, females may reduce litter size through infanticide; however, the phenomenon of maternal cannibalism under normal laboratory conditions is poorly understood. Many studies included in this review use only standard tests to measure maternal behaviour, and more ethological research would be valuable to understand problems with reproduction in laboratory strains as well as to understand the influence of different housing conditions.