Social behavior and hormonal correlates during the perinatal period in Japanese macaques

This work assessed the changes in both social interactions and estrogen met abolite excreted in feces in eight group-living Japanese macaques (Macaca f uscata). We tested the hypothesis that the social behavior of pregnant fema les shows significant changes during the late prepartum and early postpartu m period. We also tested the hypothesis that the marked fluctuation in estr ogen levels during the perinatal period is associated with the changes in s ocial behavior. We found that pregnant females withdrew from the social lif e of their group in preparation for parturition and only slowly regained th eir normal social activity after delivery. These changes were correlated wi th the fluctuation in estrogen conjugate excreted in feces, giving further evidence that hormones can enhance responsiveness to the infant and may pre dict maternal competence in macaques. We also found that the high frequency of self-grooming by pregnant females during the perinatal period may be a functional way to improve the quality of care toward an infant by a simple shifting from the care for oneself to the care for the infant after parturi tion. (C) 2001 Academic Press.