Doctoral Dissertation Research: Biomechanical Investigation of African Apes and Influences of Positional Behavior

Indiana University, Bloomington IN

Investigators

Abstract

The proposed research takes advantage of recently published fine-grained positional behavior data so that connections between African ape behavior and morphology, even at the subspecific level, can be inferred. Because the earliest human ancestors exhibit some ape-like features, a more complete understanding of African ape long bone morphology (e.g., humeral and femoral shaft shape) is necessary to infer early hominid positional adaptations. Implications of the proposed research extend beyond refining the behavior-morphology link in African apes and hominids by offering avenues of insight into the structure and function of all mammals. The proposed investigation is timely since the existence of a straightforward relationship between positional behaviors and long bone morphology has been debated recently. The PI and student have performed a preliminary analysis using 33 African ape specimens and revealed links between their behavior and morphology. For instance, higher percentages of arboreal locomotor behaviors, such as scrambling, correlated with greater long bone circularity (i.e., ratio of principle moments of area) at several measured locations. In order to complete data collection from 299 additional specimens, access to museum collections and to CT scanning facilities near each of these museum collections has been arranged. In the preliminary analysis, sample trends in shaft morphology differed depending on the measure that was used to estimate body mass. By expanding the sample, as proposed here, such apparent discrepancies between body mass estimators might be resolved and shaft morphology interpreted.