University of Calgary PRISM: University of Calgary's Digital Repository Graduate Studies The Vault: Electronic Theses and Dissertations 2016 Fission-Fusion Dynamics in Spider Monkeys in Belize Hartwell, Kayla Song Hartwell, K. S. (2016). Fission-Fusion Dynamics in Spider Monkeys in Belize (Unpublished doctoral thesis). University of Calgary, Calgary, AB. doi:10.11575/PRISM/26183 http://hdl.handle.net/11023/3497 doctoral thesis University of Calgary graduate students retain copyright ownership and moral rights for their thesis. You may use this material in any way that is permitted by the Copyright Act or through licensing that has been assigned to the document. For uses that are not allowable under copyright legislation or licensing, you are required to seek permission. Downloaded from PRISM: https://prism.ucalgary.ca UNIVERSITY OF CALGARY Fission-Fusion Dynamics in Spider Monkeys in Belize by Kayla Song Hartwell A THESIS SUBMITTED TO THE FACULTY OF GRADUATE STUDIES IN PARTIAL FULFILMENT OF THE REQUIREMENTS FOR THE DEGREE OF DOCTOR OF PHILOSOPHY GRADUATE PROGRAM IN ANTHROPOLOGY CALGARY, ALBERTA DECEMBER, 2016 © Kayla Song Hartwell 2016 Abstract Most diurnal primates live in cohesive social groups in which all or most members range in close proximity, but spider monkeys (Ateles) and chimpanzees (Pan) are known for their more fluid association patterns. These species have been traditionally described as living in fission-fusion societies, because they range in subgroups of frequently changing size and composition, in contrast with the more typical cohesive societies. In recent years the concept of fission-fusion dynamics has replaced the dichotomous fluid versus cohesive categorization, as it is now recognized that there is considerable variation in cohesiveness both within and between species. This thesis is a study of the fission-fusion dynamics in spider monkeys to quantify and explain temporal variation in subgroup size, spatial cohesion, and stability. I collected behavioural, ecological, and genetic data from a group of spider monkeys at Runaway Creek Nature Reserve in Belize from January 2008 until September 2013. I found that most subgroups were small (1-3 individuals), contained only adult females, and changed membership every 30-40 minutes. Habitat-wide fruit availability showed a weak relationship with subgroup size, contrary to what I expected, but it did explain some of the variation in subgroup stability. Likewise, degree of relatedness between individuals was not correlated with an association index that measured the likelihood that any two individuals would be in the same subgroup together. This thesis also describes the feeding ecology of the study group, and explores their genetic structure. The latter revealed some unexpected patterns: although traditionally believed to be a male philopatric, female dispersal species, male spider monkeys at Runaway Creek were no more closely related to one another than were females, and both males and females were ii residents and immigrants. As expected, given the common characterization of spider monkey males as experiencing low levels of within-group competition for females, paternity analysis revealed no reproductive skew, with all males siring offspring. Further analysis is needed to identify and understand the variables that are affecting the temporal changes in subgroup size, spatial cohesion, and stability of this group. However, this study makes an important contribution to this much larger question. iii Acknowledgements I am sincerely grateful to my supervisors, Dr. Mary Pavelka and Dr. Hugh Notman, whose constant support, encouragement, and guidance helped me to accomplish my graduate work and research. I would also like to thank the other members of my advisory committee, Dr. Linda Fedigan and Dr. Pascale Sicotte for valuable feedback and support over the years, as well as to Dr. Kathreen Ruckstuhl who has served on my defenses for Masters, candidacy exam, and PhD. And many many thanks to my external examiner, Dr. Colin Chapman. Dr. Peter Dawson, Graduate Program Director, served as the neutral chair for the oral defense, and his calm and supportive presence was much appreciated. I would also like to thank everyone (graduate students, faculty, and staff) in the Anthropology Department at the U of C, and Tracy Wyman for help with ranging data and mapping. To Jane Champion (this is for the fallen soldiers, never forget), Colin Dubrool (I purposely spelled your name wrong), Meredith Brown (sleeps like Teenager), Kayley Evans, and Brittany Dean: thank you for your friendship, dedication to the field, and for your contribution toward data which helped make this research possible. And thanks to my dear friend and mentor, Dr. Sarah Hewitt, for always being there for me during the best and worst of times. I am very grateful to Sharon Matola, Founder and Director of the Belize Zoo and Tropical Education Center for her support in helping Mary Pavelka to launch the spider monkey study at Runaway Creek Nature Reserve, along with Dr. Gil and Lillian Boese. I also thank Lillian and Gil for permission to work in the Reserve and for their ongoing iv support of the project. Local NGO Birds without Borders (Reynold Cal, Wilber Martinez, David Tzul, and Stevan Reneau) was also critical to the success of this study for their assistance with field work and for the countless times they came to the rescue when I bogged the truck in knee-deep mud or broke down along the Coastal Road. I am especially grateful to Stevan Reneau and David Tzul for sharing their knowledge of the bush and for helping me chase monkeys up and over karst hills for months on end during the long habituation process. I also want to thank Gilroy (Nico) Welsh for his assistance with chopping trails, collecting data, and for always keeping everyone in good spirits with his cool vibes. Many thanks to David Tzul and Dr. Steven Brewer for vegetation sampling and plant identification, and Gerson Garcia and Richard Usher for their assistance in the field. I would also like to thank Sharon Matola and everyone at the Tropical Education Center for providing accommodation over the years, and to Sue Hufford at Amigos for keeping me well fed and hydrated. I am grateful to Dr. Anthony Di Fiore for inviting me to work in his genetics lab at the University of Texas at Austin, and to Amely Martins for her training and guidance. A big thank you to Marie Tosa for contributing additional genotype data on the spider monkeys at Runaway Creek. I would like to thank the following agencies for the funding that made this research possible: Natural Sciences and Engineering Research Council of Canada; National Geographic; Athabasca University Academic Research Fund; Andover (New Hampshire) Service Club Scholarship; the Shelley R. Saunders Thesis Research Grant (Canadian v Association for Physical Anthropology); and the University of Calgary (URGC Dissertation Research Grant, Graduate Faculty Council Scholarship, Chancellor’s Challenge Graduate Scholarship, J.B. Hyne Graduate Scholarship, the Department of Anthropology and Archaeology, the Faculty of Graduate Studies, and the Faculty of Arts). A very special thank you to my family in New Hampshire for all their support, love, and encouragement. I couldn’t have done this without you. vi Dedication This thesis is dedicated to those with learning disabilities in academia who have to work so much harder to be where they are. vii Table of Contents Abstract ............................................................................................................................... ii Acknowledgements ............................................................................................................ iv Dedication ......................................................................................................................... vii List of Tables ..................................................................................................................... ix List of Figures ......................................................................................................................x CHAPTER 1. GENERAL INTRODUCTION ...................................................................1 Introduction ......................................................................................................................1 Background in Spider Monkey Behaviour and Social Organization ...............................8 Thesis Objectives ...........................................................................................................11 CHAPTER 2. QUANTIFYING FISSION-FUSION DYNAMICS IN SPIDER MONKEYS IN BELIZE: TEMPORAL VARIATION IN SUBGROUP SIZE, SPATIAL COHESION, AND STABILITY.............................................................17 Introduction ....................................................................................................................17 Methods .........................................................................................................................20 Results ............................................................................................................................24 Discussion ......................................................................................................................36 CHAPTER 3. THE EFFECTS OF FEEDING ECOLOGY ON FISSION-FUSION DYNAMICS IN SPIDER MONKEYS ....................................................................41 Introduction ....................................................................................................................41