This research seeks to establish the feasibility of collecting data on food material properties, ingestive behavior and masticatory behavior in wild primates in a field setting. These data will be used to investigate ecological and behavioral correlates of species-level differences in jaw morphology in a large assemblage of cranio-dental specimens from a population of monkeys living in the Ivory Coast's Tai Forest. Data on food hardness and toughness, ingestive behaviors, and sex-specific feeding profiles will be collected. Nuances of masticatory preparation (anterior vs. postcanine processing, chewing cycle rates) will be recorded as they co-vary with foods of differing material properties. Video cameras will be used to quantify chewing behavior and portable durometers to assess hardness and toughness properties of foods consumed by the four cercopithecines and three colobines inhabiting the Tai Forest. Generation of these data sets presents a number of methodological hurdles and thus the research is high risk. However, the potential payoff is significant and has a high probability of being transformative.
Feeding ecology is assumed to have had a significant influence on skull morphology in primate evolution. The relative abundance of fossil mandibles has prompted a large body of research into the functional significance of mandibular variation in living primates. Success in establishing functional linkages between jaw morphology and diet has been mixed, in part due to inadequacy of structurally-focused models of jaw strength. The data gathered under this proposal will be used for the expressed purpose of framing hypotheses designed to link specific trophic features with their morphometric counterparts. Ultimate success of this approach requires that the skeletal and dietary data be derived from a single population. Such a design is available here, however the requisite field data have yet to be collected. The activities described in this proposal provide the data sets necessary to inform species-specific hypotheses. The combination of field data on food mechanics with laboratory-based models of biomechanical performance represents a synthetic approach for establishing linkages between ecological and morphological variables in primate communities. The research is transformational because 1) identical source populations for collection of ecological and skeletal mechanical data are utilized, 2) the skeletal samples are in possession of the PI and can be modified for essential biomechanical tests of material and structural properties, and 3) the field data collected will involve variables with known and direct impacts on masticatory physiology and function. Opportunities for the convergence of such data sets are exceedingly rare, and no such study has been implemented previously.
There are multiple broader impacts from this research: (1) development of nondestructive means to assess mechanical competence in the skeleton, (2) educational opportunities for students at the PI's university, and (3) continued protection of the flora and fauna present in the Ivory Coast's Tai Forest.
