Do femoral biomechanical properties follow locomotor changes in primates? An ontogenetic study of olive baboons (Papio anubis)

Abstract

AbstractObjectivesThe locomotor repertoire of the olive baboon (Papio anubis) changes during ontogeny from a diversified pattern in infancy to a stereotyped pattern in adults. On the assumption that the femoral diaphysis adapts to variations in the loading regime, we aimed to evaluate the impact of locomotor changes on femoral biomechanical properties during the ontogeny of olive baboons.Materials and MethodsWe used the cross‐sectional geometry of 50 three‐dimensional‐reconstructed olive baboon femora of an ontogenetic sample including individuals from birth to 28 years of age and belonging to a single social group. Cross section parameters were extracted, and cortical thickness maps were produced from 20% to 80% of the femoral length.ResultsNewborns present a distribution of cortical thickness that is longitudinally symmetric and anteroposterior shaped cross sections at midshaft. From this condition, infants, juveniles and adults femoral diaphyses are all characterized by a proximal shift in cortical thickness and a mediolateralization of bending rigidity and strength at midshaft.DiscussionAs soon as locomotor autonomy is established and despite a combination of several significant locomotor modes, the biomechanical pattern remains stable during ontogeny. Our results do not reflect the changes in locomotor repertoires that occur during ontogeny of Papio anubis. We therefore advise caution when inferring complex locomotor behavior from femoral biomechanical properties.