Abstract # 163:

Scheduled for Friday, June 22, 2007 05:00 PM-07:00 PM: Session 14 (South Main Hall) Poster Presentation

Life History in Captive Japanese Macaques: Growth Rate, Dominance and Reproductive Success

N. A. DeBolt Robertson
Oregon National Primate Research Center, 505 NW 185th Ave., Beaverton, OR 97006, USA

Early life history parameters as well as social behavior may affect fitness in primates. Numerous studies have investigated this relationship in the field; however, there have been fewer studies for captive populations where ecological pressures may differ. I examined the correlation between weight, dominance status and reproductive success in female Japanese macaques (Macaca fuscata) living in a semi-natural 2-acre outdoor corral consisting of approximately 250 animals. The troop contains 12 matrilineal dominance lineages, which have been stable over several decades. For the present study, subjects (N=33) were born during four consecutive years (1999-2002), and were from the four highest (n=22) and lowest (n=11) ranking lineages. I examined body weight annually during early life development. Dominant females gained significantly more weight between the ages of three and four (a stage that corresponds to puberty) compared to subordinate females (Mann-Whitney U=179.50, p=0.025). High rank among primates is frequently associated with positive changes in growth rate, especially for juvenile females. I then examined the age at which females first gave birth for the older cohort of subjects (i.e., those born from 1999-2000; n=15) to get a measure of reproductive success. Dominant females gave birth at an earlier age than subordinate females (U=12.0, p=0.05). These data suggest that the social environment is correlated with individual differences in growth, which may impact reproductive success.