Telemetry System for Assessing Jaw-Muscle Function in Free-ranging Primates

  • Susan H. WilliamsEmail author
  • Christopher J. Vinyard
  • Kenneth E. Glander
  • Max Deffenbaugh
  • Mark F. Teaford
  • Cynthia L. Thompson


In vivo laboratory-based studies describing jaw-muscle activity and mandibular bone strain during mastication provide the empirical basis for most evolutionary hypotheses linking primate masticatory apparatus form to diet. However, the laboratory data pose a potential problem for testing predictions of these hypotheses because estimates of masticatory function and performance recorded in the laboratory may lack the appropriate ecological context for understanding adaptation and evolution. For example, in laboratory studies researchers elicit rhythmic chewing using foods that may differ significantly from the diets of wild primates. Because the textural and mechanical properties of foods influence jaw-muscle activity and the resulting strains, chewing behaviors studied in the laboratory may not adequately reflect chewing behaviors of primates feeding in their natural habitats. To circumvent this limitation of laboratory-based studies of primate mastication, we developed a system for recording jaw-muscle electromyograms (EMGs) from free-ranging primates so that researchers can conduct studies of primate jaw-muscle function in vivo in the field. We used the system to record jaw-muscle EMGs from mantled howlers (Alouatta palliata) at Hacienda La Pacifica, Costa Rica. These are the first EMGs recorded from a noncaptive primate feeding in its natural habitat. Further refinements of the system will allow long-term EMG data collection so that researchers can correlate jaw-muscle function with food mechanical properties and behavioral observations. In addition to furthering understanding of primate feeding biology, our work will foster improved adaptive hypotheses explaining the evolution of primate jaw form.


Alouatta electromyography mastication telemetry 



We thank Randy Ford and Margaret Clarke for assistance in the field and Stephan Schmidheiny and the Board of Directors of Hacienda La Pacifica for their permission to work on Hacienda La Pacifica and for their continued support and help. We also like to thank Drs. Nancy Stevens and Kristian Carlson for the invitation to contribute to this issue. The National Science Foundation (BCS-0507074, DBC-9118876, and SBR-9601766) and the Ohio University Research Committee supported our research.


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Copyright information

© Springer Science+Business Media, LLC 2008

Authors and Affiliations

  • Susan H. Williams
    • 1
    Email author
  • Christopher J. Vinyard
    • 2
  • Kenneth E. Glander
    • 3
  • Max Deffenbaugh
    • 4
  • Mark F. Teaford
    • 5
  • Cynthia L. Thompson
    • 6
  1. 1.Department of Biomedical SciencesOhio UniversityAthensUSA
  2. 2.Department of Anatomy and NeurobiologyNEOUCOMRootstownUSA
  3. 3.Department of Biological Anthropology and AnatomyDuke UniversityDurhamUSA
  4. 4.Ohio UniversityCalifonUSA
  5. 5.Center for Functional Anatomy and EvolutionJohns Hopkins UniversityBaltimoreUSA
  6. 6.Department of AnthropologyKent State UniversityKentUSA

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