Doctoral Dissertation Research: The development of social bonds in male apes

Regents Of The University Of Michigan - Ann Arbor, Ann Arbor MI

Investigators

Abstract

Friendship is an integral part of being human, and intimate and cooperative relationships are key to becoming an adult. Despite this, little is known about the nature of friendship, its function, and when in our species' history it arose. Answers to these questions may be found in our closest living relatives, chimpanzees. Like humans, adult male chimpanzees form strong social bonds with unrelated individuals, which confer benefits, including mutual aid. This project will investigate how and why friendship develops for male chimpanzees, how it relates to cooperation, competition, and the transition to adulthood, and when in life friendships are forged. The findings may be useful for reconstructing the evolutionary history of human friendship. This research will also employ two novel methods to assess growth non-invasively in wild chimpanzees. Because body size and growth are key life history variables, these methods will have far-reaching importance for biological anthropology and related fields. This project will also have social and conservation benefits. The investigators engage in educational activities in rural Uganda and the United States. In addition, the continued presence of researchers in Kibale National Park will help protect one of the last tropical rainforests in all of East Africa, and one of the principal strongholds of chimpanzees in this area. The proposed research will investigate the development of social bonds in male chimpanzees living in an exceptionally large community at Ngogo, Kibale National Park, Uganda. Behavioral observations will be carried out to assess when, why, and how social bonds between male chimpanzees are formed. The investigators will also assess the physical transition to adulthood. Digital photography, with parallel lasers acting as a scale in the photo, will be used to measure limb lengths non-invasively across a one-year period. In addition, collagen biomarkers will be implemented for the first time to assess growth in wild chimpanzees. Through a systematic study of adolescent male chimpanzee behavior, physiology, and morphology, this research aims to elucidate the development of friendship and the meaning of adulthood.