Michael Granatosky, PhD candidate from Duke University, was awarded a Leakey Foundation research grant in our most recent granting cycle for his project entitled “Gait mechanics of inverted walking: Implications for evolution of suspensory behavior.”
Michael Granatosky at the Duke Lemur Center
Specialized arm-swinging locomotion has arisen independently numerous times during the evolution of primates and yet has never appeared in any other mammalian lineage. Currently, few theories explaining the transition to specialized arm-swinging locomotion in primates have been proposed, and none of these provide an experimental framework by which to approach this question. My dissertation focuses on the mechanics of below-branch quadrupedalism, which is a form of suspensory locomotion commonly seen in primates and other mammals that requires few anatomical modifications. The goal of my project is to understand the proximate strategies mammals use to adjust mechanically to below-branch quadrupedal locomotion and then determine whether below-branch quadrupedal locomotion relates to the ultimate evolution of specialized arm-swinging locomotion in primates.
To answer these questions, I will collect locomotor data from primates, sloths, and bats during a number of experimental comparisons. First, I will collect locomotor data from primates walking above and below a runway. This comparison will determine what aspects of locomotor behavior changes between above and below-branch quadrupedal locomotion. Next, I will compare the mechanics of below-branch quadrupedal locomotion between primate and non-primate mammals. This will determine whether there are multiple strategies for adopting below-branch quadrupedal locomotion, or whether all animals are moving in a similar fashion. Finally, I will compare the mechanics of below-branch quadrupedal locomotion with specialized arm-swinging locomotion in primates to determine if below-branch quadrupedal locomotion may have served as a locomotor precursor to specialized arm-swinging locomotion.