This research addresses a hypothesis concerning the nature of the shift to bipedal locomotion in our earliest hominid ancestors. To address the origin of bipedalism is to address one of the most fundamental questions about what it means to be human. Though debate exists about whether bipedalism serves to define the human family, Hominidae, it is clear that becoming bipedal was the critical first step in the emergence of the human form, preceding all other major morphological adaptations. Understanding what it means to be human from a biological and evolutionary standpoint begins with understanding the functions of bipedalism.
This study is a two-phase project designed to examine the hypothesis that the shift to bipedalism among our Miocene ancestors was due to energy savings associated with bipedal locomotion. The project addresses two primary questions. First, to what extent do energy costs during bipedal locomotion differ from energy costs during quadrupedal locomotion in chimpanzees? Answering this question will consist of measuring energy expenditure in a diverse set of adult chimpanzees of both sexes during bipedal and quadrupedal locomotion on a treadmill. Second, have current methods of measuring day journey length in free-ranging populations of chimpanzees systematically underestimated the actual daily travel distance of these animals? This will be addressed in a 6-month field study of day journey length in a habituated population of free-ranging chimpanzees at the Ngogo site in Kibale National Park, Uganda, Africa. Four methods of measuring day journey length will be employed and compared to measurements obtained through pace counting in order to obtain a defendable measure of day journey length for free-ranging chimpanzees and to determine to what extent current methods underestimate actual daily travel distance.
The broader impacts of this research are as follows. This project will provide undergraduate student assistants with the opportunity for experience, participation and training in the methods of scientific research at the graduate level. Undergraduate assistants will be recruited from the student membership of the Mentorships for Undergraduate Researchers in Agriculture, Letters and Science (MURALS) program at the University of California. MURALS provides funding for under-represented and minority students interested in gaining experience doing graduate-level research while still at the undergraduate level. This research will establish important collaborative partnerships between the School of Veterinary Medicine and the Department of Anthropology at the University of California, Davis, laying the groundwork for future interdisciplinary studies. This project will also establish an important partnership between the University of California and People and Chimps Together (PACT), a non-profit organization dedicated to the care of chimpanzees retired from medical research and from work in the entertainment industry. This project will assist PACT in furthering the creation of an educational facility to introduce the public to the behavior and conservation needs of chimpanzees. The benefits of this research to society at large include potential contributions to several areas of modern health care including sports medicine, veterinary medicine and the emerging field of evolutionary medicine. Moreover, the desire to understand our origins is ubiquitous in human society. This research will provide a deeper understanding of those origins.
