The influence of the social environment on sexual maturation of female deermice (Peromyscus maniculatus bairdi)

Summary Female deermice housed from weaning with groups of five females, five males or five males plus five females had significantly smaller uteri at 35–38 days of age compared to females reared alone. The uterine weights of females reared in the three grouped treatments did not differ significantly among themselves nor did those reared alone or with another animal of either sex. Uterine and ovary weights revealed no significant inhibition or stimulation of sexual maturation dependent upon sex of the adult conspecific with which young females were housed. The number of conspecifics (five or more of either sex) housed with young females was of primary importance in the retardation of uterine development observed.