Effects of male odor during infancy on the maturation, behavior, and reproduction of female mice

Infant female mice who were exposed to the odor of adult male mice of the same strain in the presence or absence of the mother were compared with mice who were not exposed with respect to maturation, open-field behavior, and reproductive success. Exposure lasted 4 hr daily during days 4–18 post-partum. No significant differences were found between the groups in their rates of growth or the age of ear, eye, and vaginal opening. However, the exposed groups displayed first estrus significantly earlier than non-exposed groups: the group exposed in the presence of the mothers showing the earliest first estrus of all 4 groups.