The primary objective of this research is to determine the adaptive significance of muscular and bony features distinguishing humans from nonhuman primates, and distinguishing one primate from another. This will enable a more accurate reconstruction of the lifestyles of ancient primates, particularly the ancestors of humans. Most of the influential theories about ancestral primate ways of life and the adaptive significance of features distinguishing humans, apes, and monkeys have relied on the determination of structural differences between living primates that differ in their behaviors. But, the link between structure and behavior remains tenuous without the missing element of function. The approach of the investigators provides this missing element by concentrating on the in vivo physiological technique of telemetered electromyography (combined, when appropriate, with force-plate and motion analyses). Studies conducted on nonhuman primates and humans during regular locomotor and voluntary behaviors will establish the actual roles of individual muscles in these behaviors and provide data necessary to explain many of the muscular and bony specializations of primates, including humans. Explanation of bony features will promote more accurate reconstruction of fossil lifestyles; explanations of uniquely human muscular traits will point to those behaviors that led to the major anatomical reconstruction characterizing our species.
