The goal of this research is to investigate the factors responsible for curvature in the phalanges (the bones of the fingers and toes) in higher primates. Primates that regularly grip branches during movement appear to have more curved phalanges than those that walk on the ground. As such, finger bones have historically been very useful for interpreting behavior in fossil species, including early human ancestors. However, we do not understand 1) what aspects of the mechanics of arboreal locomotion lead to phalangeal curvature and 2) how curvature develops. This research will incorporate new analytical (i.e., finite element analysis) and data acquisition (i.e., pressure sensor pads, strain gauges on cadavers) techniques to test existing hypotheses regarding phalangeal curvature by comparing how living arboreal and terrestrial primates use their hands during locomotion. Finally, the debate over how to interpret primitive morphology, important to all paleontologists interested in the reconstruction of behavior from fossil morphology, will be addressed by examining whether or not phalangeal curvature develops in response to loads experienced during growth or whether curvature is merely `phylogenetic baggage`.
