Abstract # 932 Event # 45:

Scheduled for Thursday, August 18, 2005 04:15 PM-04:45 PM: Session 6 (Crystal Ballroom) Oral Presentation

How Males Get the Mommy Factor - With a Little Help from their Hormones

T. E. Ziegler1,2 and C. T. Snowdon1,2
1University of Wisconsin, National Primate Res. Ctr., 1220 Capitol Court, Madison, WI 53711, USA, 2Department of Psychology
     Cooperatively breeding male marmosets and tamarins are highly parental. In the cotton-top tamarin, Saguinus oedipus, fathers are critical for infant survival in the first few days of life and spend more time carrying infants than mothers. What stimulates this high level of infant care giving found in male marmoset and tamarin monkeys? We have been documenting and investigating changes in “maternal” hormones in both male common marmosets, Callithrix jacchus, and cotton-top tamarins to determine how they might influence males to invest highly in their offspring. Prolactin may be involved in many aspects of preparing for parenting such as physical, hormonal and behavioral changes occurring in fathers prior to the birth of their offspring. Plasma prolactin increases significantly in father common marmosets during the third gestational month ( P = 0.01). Urinary prolactin increases in experienced father cotton-top tamarins across the gestational months with significant midpregnancy elevations (P < 0.05, month 3 is significantly higher than month 1). Males of both species show weight changes during the gestation related to infant care. Cotton-top tamarin males respond to their mate’s pregnancy with increased prolactin and increased affiliation. We suggest that prolactin may be involved in preparing male marmosets and tamarins for their role in infant care giving. Funding provided by NIH grants: MH35215, MH070423, RR000167.