Vertical climbing is thought to have played a major role in the evolution of locomotor specializations within primates, particularly in the evolution of hindlimb musculature important for bipedal locomotion by humans. Little is known, however, about how muscles use energy during climbing in primates. As a primarily arboreal radiation, all primates regularly climb. Long limbs and long stride lengths used by some primates during climbing are argued to have been important in the evolution of suspensory locomotion and bipedalism. The data collected through this project will fill a critical gap in knowledge concerning the mechanics of climbing and the relationship between postcranial anatomy and metabolic costs for this important locomotor behavior. This research will collect data on the three-dimensional biomechanics of climbing and relate these mechanics to hindlimb morphology and to the energy costs of climbing in primates. Research will be conducted at the West Virginia School of Osteopathic Medicine, Lewisburg, WV, Duke University and the Duke Lemur Center, Durham, NC, and the Michale E. Keeling Center for Cancer Research, Bastrop. TX. Eight species of primates will be examined across a range of size, ecology, and morphology. The results of this study will provide the first quantitative data on power production at the hindlimb, how power production differs with variation in hindlimb morphology, and how power production relates to the energetic costs of climbing in non-human primates. Such data will be important for understanding primate adaptations to climbing, and ultimately the evolution of specialized locomotion like bipedalism.
These topics are highly important to the understanding of the appearance of early primates, as well as the evolution of human, bipedal locomotion.
This project supports the development of women in science by contributing to an early-career, female faculty member's research. It also contributes to the development of scientific research in a geographically under-represented area of the country (West Virginia). Additionally, this project is a multinational collaboration, and fosters scientific research between the multiple institutions. This project also intends to directly involve graduate students from the West Virginia School of Osteopathic Medicine and undergraduates from Duke University in this research. Finally, the results of this research will be communicated to the scientific community at professional meetings and through publications, and to the broader communities in which the PI and co-PIs reside, through both volunteer work at local museums and public talks given at the respective institutions.
A fundamental issue in anthropology is the effect of climbing on the evolution of the locomotor repertoire of primates, particularly in the diversification of early primates and the evolution of bipedalism in the human lineage. Although many studies have documented the biomechanics of moving horizontally, few have examined the biomechanics of climbing across a wide range of primates, especially those considered to be approximately the size of early primates. Thus, we have a limited understanding of the factors involved in the evolution of a variety of primate morphologies. In this project, we examined the energy costs of climbing and compared those with the work performed during climbing by primates of various body sizes and shapes. Specifically, we asked what effects body size and shape have on the cost of climbing and do primates with different shapes climb differently. Three-dimensional video, along with force data, were collected during climbing by 7 species of primates on a vertical pole (used to simulate tree branches). Joints were digitized in the videos and these landmarks defined the angles that the limbs were at during different events of the climbing. These angles were compared to energy use data from previously collected studies. Results indicate that primate species that are purported to be better adapted to climbing, and climb more often, do so in a manner different than more generalized species. All species, however, use a similar amount of mass-specific energy to climb. These results suggest that climbing can be accomplished by a variety of morphologies, and that those morphologies, which are better adapted to climbing are not necessarily more efficient. Thus, the evolution of specialized morphology may not have been influenced by energy use, but rather by the opening of new resources and possibly new niches. Thus, the diversification of early primates allowed various species to exploit their environment in multiple, different ways. This is the first study to report the biomechanics of climbing in primates of small sizes. It is hoped that these data will serve as a foundation for other researchers seeking to understand primate climbing in general. In terms of broader impacts, this study a) supported the research activities of several young female scientists, including a high school student in a rural, low-income area of the country, b) demonstrated how science is used and interpreted to local elementary students, and c) fostered research collaborations across domestic institutions and internationally.
