The 82nd Annual Meeting of the American Association of Physical Anthropologists (2013)


How hard can it be? Exploring the feeding ecology of sakis

MARILYN A. NORCONK.

Department of Anthropology and School of Biomedical Sciences, Kent State University

Thursday Afternoon, 200DE Add to calendar

The Pitheciinae have highly specialized dentition. There is now a clear association between extraction and mastication of seeds (their preferred resources) and a dental complex that consists of procumbent incisors, large, laterally splayed canines and flat, crenulated molars with thin, decussating enamel. This trait complex is best developed in the largest-bodied genera (Cacajao and Chiropotes), scaled down with smaller-bodied Pithecia, and essentially absent in Callicebus, the primitive member of the clade. Warren Kinzey, trained as an anatomist, was a pioneer in adapting simple tools borrowed from soil science to generate a quantitative assessment of what wild sakis eat. Warren and I initiated feeding ecology studies in Suriname and Venezuela in 1986 that would define the limits, as well as variability and subtleties of ingestion and mastication of two species: Pithecia pithecia and Chiropotes satanas/sagulatus. In a nutshell, sakis use canines to generate cracks in fruit pericarp or brittle seed coats. They use procumbent lower canines to plane the surface of thick pericarps or scrape lipid-rich mesocarp from palm nuts, and crenulated molars to position wet, slippery seeds during mastication. They ingest both young seeds and (more resistant) mature seeds. If they have fallback foods, they do not seem to be related to food hardness, yet their use of very hard fruit and seeds is relatively rare. Dental adaptations enable sakis and uakaris to open well-protected fruit and brittle seed coats and provide feeding options in a complex, labile environment.

Research funded by the National Science Foundation.

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