Preparental hormone levels and parenting experience in male cotton-top tamarins, Saguinus oedipus

Male cotton-top tamarins, Saguinus oedipus, display hormonal changes associ ated with parenting prior to the birth of their infants. Here we examined t he hormonal changes that occurred in experienced and inexperienced fathers during the postconception period, prior to the birth of infants. Noninvasiv e techniques were used to collect urine from 10 male cotton-top tamarins (5 experienced and 5 inexperienced breeders) three times weekly during the 6- month gestation period. Samples were analyzed for prolactin, testosterone, dihydrotestosterone (DHT), and cortisol, averaged by gestational month. Exp erienced males showed elevated prolactin during the mate's 3rd gestational month, and the elevation correlated with the number of infants surviving fr om the previous birth (0, 1, and 2) but not with outcome of the current pre gnancy. However, an experienced male with no infants present stilt showed e levated prolactin and some inexperienced males showed elevated prolactin ju st before parturition, suggesting noninfant cues are also important. White prolactin levels were influenced by the mate's prior infant experience, tes tosterone revels did not differ between experienced and inexperienced males . Testosterone levels were significantly elevated for ail males during the 3rd, 4th and 5th months but had no relationship with number of infants pres ent or with outcome of current pregnancy. DHT decreased during the second h alf of pregnancy compared with testosterone but this finding was not consis tent for every male. No significant changes occurred in cortisol levels. Th ese results suggest that infant-rearing experience affected the hormonal re sponsitivty of the male to his mate's current pregnancy. (C) 2000 Academic Press.