Abstract # 1915 Event # 3:

Scheduled for Thursday, August 17, 2006 09:45 AM-10:00 AM: Session 1 (Regency East #1) Oral Presentation


J. M. Kamilar1, T. M. Franz1, A. Koenig2 and C. Borries2
1Stony Brook University, Interdepartmental Doctoral Program in Anthropological Sciences, Stony Brook, NY 11794-4364, USA, 2Department of Anthropology, Stony Brook University, Stony Brook, NY, 11794-4364, USA
     Hanuman langurs (Semnopithecus entellus) display a variable social organization throughout their geographic range, with groups either containing one or multiple adult males to varying degrees. Previous studies have attributed several factors to explain this variability, usually focusing on ecological and/or demographic effects and its relationship to reproductive seasonality. Yet, these factors may be confounded due to anthropogenic effects since Hanuman langurs often live in close proximity to humans, and are frequently provisioned. The purpose of this study was to simultaneously examine the potential effects of ecological, demographic, and anthropogenic factors on the number of adult males per group, the percentage of one-male groups in a population, and birth season length. Data were obtained from the published literature for over 25 populations. Several predictor variables were used in stepwise multiple regressions. The results showed that the degree of provisioning and population density were negatively related to the number of adult males per group, and positively related to the percentage of one-male groups in a population (all p<0.05). In addition, increased levels of provisioning were related to a longer mating season (p<0.10). These findings clarify previous studies that did not include provisioning data. Food provisioning extends the mating season providing the opportunity for a single male to effectively monopolize several females. This scenario supports hypotheses of social group formation due to the degree of mating synchrony.