Doctoral Dissertation Research: Examining the Energetics Hypothesis for the Origin of Hominid Bipedalism

这项研究解决了一个关于我们最早的人类祖先向两足运动转变的本质的假设。研究两足动物的起源，就是在研究一个最基本的问题，即作为人类意味着什么。尽管关于两足行走是否定义了人类家族（原始人）存在争议，但很明显，成为两足行走的人是人类出现的关键第一步，先于所有其他主要形态适应。从生物学和进化的角度理解人类意味着什么，首先要理解两足动物的功能。这项研究分为两个阶段，旨在检验中新世祖先向两足行走的转变是由于与两足运动相关的能量节约这一假设。该项目解决了两个主要问题。首先，黑猩猩两足运动时的能量消耗与四足运动时的能量消耗在多大程度上不同？为了回答这个问题，我们将测量不同种类的成年黑猩猩在两足和四足行走在跑步机上时的能量消耗。第二，目前在自由放养的黑猩猩种群中测量日行程长度的方法是否系统性地低估了这些动物的实际日行程距离？这一问题将在非洲乌干达基巴莱国家公园Ngogo地点对自由放养的习惯性黑猩猩进行为期6个月的日行程长度实地研究后得到解决。我们将采用四种测量日行程长度的方法，并将其与通过步伐计数获得的测量结果进行比较，以便对自由放养的黑猩猩的日行程长度进行可靠的测量，并确定目前的方法在多大程度上低估了实际的日行程距离。本研究的广泛影响如下。该项目将为本科生助理提供在研究生阶段体验、参与和培训科学研究方法的机会。本科助理将从加州大学农业、文学和科学本科研究人员指导计划（MURALS）的学生会员中招募。MURALS为有兴趣在本科阶段获得研究生水平研究经验的弱势群体和少数民族学生提供资金。这项研究将在加州大学戴维斯分校兽医学院和人类学系之间建立重要的合作伙伴关系，为未来的跨学科研究奠定基础。该项目还将在加州大学和人类与黑猩猩共同组织（PACT）之间建立重要的伙伴关系。PACT是一个非营利性组织，致力于照顾从医学研究和娱乐界退休的黑猩猩。该项目将协助PACT进一步建立一个教育设施，向公众介绍黑猩猩的行为和保护需求。这项研究对整个社会的好处包括对现代卫生保健的几个领域的潜在贡献，包括运动医学、兽医学和新兴的进化医学领域。此外，在人类社会中，了解我们的起源的愿望是无处不在的。这项研究将对这些起源提供更深入的了解。

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.