Maternal behavior of primiparous females in inbred strains of mice: a detailed descriptive analysis.

In the present study, we compared the maternal and non-maternal behaviors of primiparous females in both the light and dark phases during 3 weeks postpartum in five inbred strains of mice (BALB/c, CBA/Ca, C3H/He, C57BL/6, and DBA/2) to examine the strain differences in the behaviors in detail. Generally, nursing postures (arched-back, blanket, and supine) and pup lickings (anogenital and body) occurred more frequently in the light phase, whereas nest building occurred more frequently in the dark phase. As pups grew, arched-back and blanket nursing, anogenital and body licking, and nest building decreased, but supine nursing slightly increased. The present results revealed strain-specific variations in maternal behavior. In general, BALB did not engage in maternal behavior very vigorously, but the other four strains actively did. The patterns of strain differences were not parallel between the subcomponents of nursing posture or pup licking. CBA showed more arched-back and supine nursing, and DBA showed more blanket nursing. C57 and CBA showed more anogenital licking, while C3H and DBA showed more body licking. Strain differences were also found for the changes across postpartum days in almost all behaviors. These findings provide information to examine the effects of genetic and environmental factors on the development of maternal behavior in mice.