Abstract # 185:

Scheduled for Friday, June 22, 2007 05:00 PM-07:00 PM: Session 14 (North Main Hall E) Poster Presentation

EMG telemetry in free-ranging primates: pilot data from howling monkeys (Alouatta palliata) at La Pacifica, Costa Rica

S. H. Williams1, C. J. Vinyard2, K. E. Glander3, M. F. Teaford4, M. Deffenbaugh5 and C. L. Thompson6
1Ohio University, Athens, USA, 2NEOUCOM, 3Duke University, 4Johns Hopkins University School of Medicine, 5ExxonMobil, 6Kent State University
     Laboratory-based electromyographic (EMG) studies are integral for understanding primate masticatory function and evolution. By directly linking jaw-muscle function during chewing to mandibular form, these studies provide the foundation for adaptive hypotheses relating primate jaw form to diet. However, because these studies elicit mastication using foods atypical of wild primate diets, their ecological and evolutionary relevance is unclear. This lack of an ecologically-relevant biological role is further confounded by the fact that jaw-muscle activity is influenced by food mechanical properties, which may influence primate food choice in the wild. To more critically test adaptive hypotheses of primate masticatory form and function, we developed a telemetry system for recording jaw-muscle EMGs during mastication by wild primates feeding naturally. The telemetry system amplifies, filters and transmits up to eight electrode signals as an FM audio signal to a receiver. This signal is digitally recorded and demodulated producing separate EMG waveforms for each electrode. Prior to field use we verified that the system performed similarly to a non-telemetered system used in collecting primate EMG data. We tested the telemetry system in the field on mantled howling monkeys at La Pacifica, Costa Rica. Jaw-muscle EMGs were collected from two individuals during the mastication of leaves and berries, revealing a qualitative variation relative to food toughness. Supported by NSF BCS-0507074, BCS-0552285, IOB-0520855, and the Ohio University Research Committee.