V.V. Venkataraman and H. Glowacka contributed equally to the manuscript.
Effects of dietary fracture toughness and dental wear on chewing efficiency in geladas (Theropithecus gelada)
Article first published online: 17 JUL 2014
Copyright © 2014 Wiley Periodicals, Inc.
American Journal of Physical Anthropology
Volume 155, Issue 1, pages 17–32, September 2014
How to Cite
Venkataraman, V. V., Glowacka, H., Fritz, J., Clauss, M., Seyoum, C., Nguyen, N. and Fashing, P. J. (2014), Effects of dietary fracture toughness and dental wear on chewing efficiency in geladas (Theropithecus gelada). Am. J. Phys. Anthropol., 155: 17–32. doi: 10.1002/ajpa.22571
- Issue published online: 6 AUG 2014
- Article first published online: 17 JUL 2014
- Manuscript Accepted: 7 JUL 2014
- Manuscript Received: 14 MAR 2014
- Clare Garber Goodman Fund, Department of Anthropology at Dartmouth College
- National Science Foundation's Graduate Research Fellowship Program
- National Geographic Young Explorer's Grant
- Small Research Grant, American Society of Primatologists
- Institute of Human Origins Fellowships, Arizona State University
- CSU Fullerton
- Cleveland Metroparks Zoo
- Margot Marsh Biodiversity Foundation
- Pittsburgh Zoo
- Primate Conservation Inc.
- Dean Gibson and San Diego Zoo
- Gisela and Norman Fashing
- Donna and Karl Krueger
- Anita and Hans-Peter Profunser
- Christopher Schroen
- food mechanical properties;
- fecal particle size;
- dental topography;
- fallback foods
Chewing efficiency has been associated with fitness in mammals, yet little is known about the behavioral, ecological, and morphological factors that influence chewing efficiency in wild animals. Although research has established that dental wear and food material properties independently affect chewing efficiency, few studies have addressed the interaction among these factors. We examined chewing efficiency, measured as mean fecal particle size, as a function of seasonal shifts in diet (and corresponding changes in food fracture toughness) in a single breeding population of a grazing primate, the gelada monkey, at Guassa, Ethiopia. We also measured dental topographic traits (slope, angularity, and relief index) and relative two- and three-dimensional shearing crest lengths in a cross-sectional wear series of gelada molars. Chewing efficiency decreased during the dry season, a pattern corresponding to the consumption of foods with higher fracture toughness. Older individuals experienced the most pronounced decreases in chewing efficiency between seasons, implicating dental wear as a causal factor. This pattern is consistent with our finding that dental topographic metrics and three-dimensional relative shearing crest lengths were lowest at the last stage of wear. Integrating these lines of behavioral, ecological, and morphological evidence provides some of the first empirical support for the hypothesis that food fracture toughness and dental wear together contribute to chewing efficiency. Geladas have the highest chewing efficiencies measured thus far in primates, and may be analogous to equids in their emphasis on dental design as a means of particle size reduction in the absence of highly specialized digestive physiology. Am J Phys Anthropol 155:17–32, 2014. © 2014 Wiley Periodicals, Inc.