The influence of experimental manipulations on chewing speed during in vivo laboratory research in tufted capuchins (Cebus apella)
Article first published online: 5 APR 2011
Copyright © 2011 Wiley-Liss, Inc.
American Journal of Physical Anthropology
Volume 145, Issue 3, pages 402–414, July 2011
How to Cite
Thompson, C.L., Donley, E.M., Stimpson, C.D., Horne, W.I. and Vinyard, C.J. (2011), The influence of experimental manipulations on chewing speed during in vivo laboratory research in tufted capuchins (Cebus apella). Am. J. Phys. Anthropol., 145: 402–414. doi: 10.1002/ajpa.21514
- Issue published online: 14 JUN 2011
- Article first published online: 5 APR 2011
- Manuscript Accepted: 30 JAN 2011
- Manuscript Received: 20 SEP 2010
- NSF. Grant Number: BCS-0552285
- experimental conditions
Even though in vivo studies of mastication in living primates are often used to test functional and adaptive hypotheses explaining primate masticatory behavior, we currently have little data addressing how experimental procedures performed in the laboratory influence mastication. The obvious logistical issue in assessing how animal manipulation impacts feeding physiology reflects the difficulty in quantifying mechanical parameters without handling the animal. In this study, we measured chewing cycle duration as a mechanical variable that can be collected remotely to: 1) assess how experimental manipulations affect chewing speed in Cebus apella, 2) compare captive chewing cycle durations to that of wild conspecifics, and 3) document sources of variation (beyond experimental manipulation) impacting captive chewing cycle durations. We find that experimental manipulations do increase chewing cycle durations in C. apella by as much as 152 milliseconds (ms) on average. These slower chewing speeds are mainly an effect of anesthesia (and/or restraint), rather than electrode implantation or more invasive surgical procedures. Comparison of captive and wild C. apella suggest there is no novel effect of captivity on chewing speed, although this cannot unequivocally demonstrate that masticatory mechanics are similar in captive and wild individuals. Furthermore, we document significant differences in cycle durations due to inter-individual variation and food type, although duration did not always significantly correlate with mechanical properties of foods. We advocate that the significant reduction in chewing speed be considered as an appropriate qualification when applying the results of laboratory-based feeding studies to adaptive explanations of primate feeding behaviors. Am J Phys Anthropol, 2011. © 2011 Wiley-Liss, Inc.