Doctoral Dissertation Improvement: Biomechanical and Behavioral Significance of the Neanderthal Femur

Suny At Albany, Albany NY

Investigators

Abstract

Many researchers have suggested that the greater robusticity and resultant strength of Neandertal femora, compared with those of modern humans, is due to extended use while foraging and hunting. This is known as the mobility hypothesis. This study examines that hypothesis by examining skeletal features and ranging behaviors in a large sample of living primates to determine if use equates with greater robusticity. Results will inform the fields of anthropology, primatology, orthopedics, engineering, and quantitative genetics. The study also impacts understanding of the femur's mechanical environment, which could aid the development of hip prosthetics. Furthermore, this study improves understanding of the correlation between genetics and femoral morphology, and promotes interdisciplinarity between engineering and social sciences. The Neanderthal femur differs from that of recent modern humans in four ways that suggest it is more robust, or biomechanically stronger: it is more curved, has thicker bone, a round rather than elliptical shaft, and a smaller neck-shaft angle. These differences may be explained by the mobility hypothesis. Due to subsistence strategies relying heavily on the exploitation of animal resources, Neanderthals may have been traveling farther than modern humans in search of food, and would thus be loading their lower limbs to a greater extent. This study tests the mobility hypothesis using a three phase approach. The first phase establishes a comparative basis relating mobility to femoral skeletal features in 35 species of living primates with documented ranging behavior, using a method that will produce and disseminate hundreds of computerized 3D surface models. The second phase analyzes the degree to which key skeletal features are heritable or environmentally produced using 21 strains of inbred laboratory mice totaling 413 individuals. The final phase explores the strength of complete Neanderthal and modern human femora within each species' particular anatomical context, using an engineering technique (finite element analysis) designed to investigate how complex structures respond to loads, and include the impact of realistic muscle and hip joint reaction forces.