Abstract # 224:

Scheduled for Thursday, August 18, 2005 11:45 AM-12:00 PM: Session 2 (Mayfair Room) Oral Presentation

The effects of social rank on growth patterns in captive adolescent female baboons (Papio hamadryas anubis)

T. Mueller
University of New Mexico, Department of Anthropology, University of New Mexico, Albuquerque, NM 87131, USA
     This present study aims to measure differences in growth across various levels of competitive ability (measured by dominance rank) in a captive population, specifically by addressing allocation to competing areas of growth, including skeletal length, body fat, and lean muscle mass. Data on social rank, resource acquisition, and growth patterns were collected on 61 adolescent female baboons (Papio hamadryas anubis) housed as part of a semi free-ranging breeding population at the Southwest Foundation for Biomedical Research and Southwest National Primate Center in San Antonio, Texas. These data indicate that high social rank confers advantages both in the absolute crown-rump size of females (P = 0.01), and the age at which crown-rump growth slows (compared respectively to middle and low ranking females, P = 0.009, 0.003). Social rank likewise affects body weight, both in terms of absolute weight (P = 0.003, 0.000) and rate of weight gain (P = 0.028, 0.001), but not the age at which weight gain slows. Social rank has no effect on body fat, as measured through subscapular skinfold. Social rank confers significant advantages in terms of body mass index (P = 0.006, 0.000). This pattern of being heavier for height without having the corresponding increases in body fat indicate that high ranking females are allocating energy towards growth in lean muscle mass, thereby making themselves more effective mothers and feeders.