Abstract # 7:

Scheduled for Thursday, June 21, 2007 10:45 AM-11:00 AM: Session 1 (North Main Hall C/D) Oral Presentation


K. Sayers
Kent State University, School of Biomedical Sciences, Program in Biological Anthropology, Kent, OH 44242-0001, USA
     Extractive foraging, the exploitation of hidden food items, is a frequent component in models of primate intelligence, and colobine monkeys are often categorized as nonextractive foragers. I report behavioral and ecological data related to extractive foraging in two troops of Himalayan gray langurs ranging above 3000m elevation at Langtang National Park, Nepal. Based on scan samples taken over 12 months during 2003 and 2004, hidden foods comprised 16.1% of langur annual diet, and as high as 39.6% of monthly diet. Four general categories, and 6 specific types, of extractive foraging were identified. Commonly observed were partial item consumption (removing seed covers, peeling husks) and the excavation of underground storage organs (digging, surface scratching). Rare behaviors included prying bark (arthropod foraging) and searching for foods under obstacles (rocks). Using data from the annual phenology and scan samples, the percentage of monthly diet comprising hidden foods was not related to overall food abundance [Spearman Rank Order Correlation, a=0.05], but was significantly and negatively related to the consumption of deciduous young leaves. Extractive foraging is a key element of the Himalayan langur feeding adaptation, and aids their survival in this comparatively marginal habitat. Supported by L.S.B. Leakey Foundation and Kent State University.