An Ecogeographic Study of Body Proportion Development in the Sadlermiut Inuit of Southampton Island, Nunavut
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An Ecogeographic Study of Body Proportion Development in the Sadlermiut Inuit of Southampton Island, Nunavut by Natalie Symchych A thesis submitted in conformity with the requirements for the degree of Doctor of Philosophy Graduate Department of Anthropology University of Toronto c Copyright 2016 by Natalie Symchych Abstract An Ecogeographic Study of Body Proportion Development in the Sadlermiut Inuit of Southampton Island, Nunavut Natalie Symchych Doctor of Philosophy Graduate Department of Anthropology University of Toronto 2016 This thesis explores growth status and body proportion development in past North Amer- ican Arctic populations. Living in one of the most extreme environments on the planet, Arctic foragers provide an opportunity to explore how human morphological variation is shaped by growth and climate. The study focuses on the Sadlermiut Inuit, who lived on Southampton Island in Hudson Bay, Nunavut. This main sample is comprised of 111 juveniles and 160 adults (62 F, 52 M, 46 und). Comparative samples are derived from Northwest Hudson Bay, Point Hope (Alaska), and Greenland, and are comprised of 106 juveniles and 151 adults (76 F, 75 M). Growth status in four long bones is assessed by comparing the samples' tempo of growth to normative values from a modern North American sample. Body proportion development is assessed by calculating brachial index, crural index, and limb length relative to skeletal trunk height. Plots of index values versus dental age are assessed visually, and compared to results from the literature. Sadlermiut individuals who died as juveniles show a predominant pattern of growth faltering as compared to the North American tempo of growth. Most Sadlermiut juveniles who died in infancy either began life lagging in proportional growth, or fell behind quickly after birth. Most Sadlermiut juveniles who died later in childhood/adolescence had con- tinued to falter in growth, indicating either insufficient, or a lack of, catch-up growth. ii This contrasts with Point Hope, which showed a broad range of growth outcomes: indi- viduals with growth in line with the North American tempo, as well as individuals with lagging and accelerated growth. The analysis of body proportion development demonstrates that Sadlermiut infants exhibit a wide range of index values, and adult-type body proportions appear by early- to mid-childhood. Adult proportionality is achieved by most older Sadlermiut juveniles, despite a lag in linear growth. This demonstrates that linear growth is more environ- mentally labile, while body shape is more conserved. Moreover, the timing of body proportion development is consistent across samples from this study and the literature, suggesting a consistent pattern of growth with regard to body proportionality, regardless of latitude/climate and ultimate adult proportionality. iii Acknowledgements I owe thanks to many people for their support and assistance over the course of my doctoral degree. First and foremost is my supervisor, Susan Pfeiffer. She has been continually supportive of me and this project, and I am deeply grateful for her guidance these past five years. I am grateful to the members of my examination committee for their excellent input and suggestions, which helped me to improve this thesis. I benefited greatly from the guidance and perspective offered by Tracey Galloway, Tracy Prowse, Michael Schillaci, and Daniel Sellen. I thank the curators and curatorial staff who gave me the opportunity to study the skeletal remains under their care: Janet Young and Jerry Cybulski of the Canadian Museum of History; Gisselle Garcia of the American Museum of Natural History; and Niels Lynnerup of the University of Copenhagen. I am grateful to the Inuit Heritage Trust and the Greenland National Museum and Archives for granting permission to study the Canadian and Greenlandic skeletal collections. My research travel was supported by funding from the University of Toronto Department of Anthropology, and the School of Graduate Studies. My degree has been supported by scholarships from the Social Sciences and Humanities Research Council, the Ontario Graduate Scholarship program, and the University of Toronto. A big thank you to Janet Young, for her continued mentorship and support. Thank you for hiring me ten years ago, and for encouraging me to explore my interests. And thank you to Megan Gardiner of the CMH for all her help from afar. I wish to thank my family and friends for their love and support. To my parents, who have been outstandingly supportive, and generous with their proof-reading skills. And finally, thank you to my partner Brent Pym | for the abundant love and encouragement, for the tech support, and for the (as always) excellent food. iv Contents 1 Introduction1 1.1 Hypotheses..................................3 2 Background5 2.1 Body form and ecogeographic expectations.................5 2.1.1 Non-human ecogeographic patterning................6 2.1.2 Classical approaches to ecogeographic patterning in humans...7 Adult body proportions in living populations............7 Adult body proportions in past populations............9 Juvenile body proportions in modern (Arctic) populations.... 15 Juvenile body proportions in past populations........... 17 2.1.3 Emerging perspectives on human ecogeographic patterning.... 20 Tissue economy............................ 20 Childhood growth trade-offs..................... 21 Allometry............................... 23 Population structure and history.................. 25 2.1.4 Methodological considerations.................... 28 2.2 Linear growth................................. 29 2.2.1 General pattern and normal variability of linear growth...... 29 Longitudinal and cross-sectional growth studies.......... 32 v 2.2.2 Effects of growth on body proportion development......... 33 2.2.3 Growth studies in past populations................. 36 Humphrey methodology and the Denver Growth Study...... 37 2.2.4 Considerations for the study of growth in the Arctic........ 39 2.3 Main sample: the Sadlermiut Inuit..................... 43 2.3.1 Sadlermiut introduction and ethnographic contact......... 43 2.3.2 Sadlermiut within Arctic population history............ 44 2.3.3 Sadlermiut as a single population.................. 46 2.4 Arctic contextual information........................ 47 2.4.1 Ethnographic information...................... 47 2.4.2 Inuit diet and the health `paradox'................. 51 2.4.3 Infant mortality data in recent historical Inuit populations.... 53 3 Materials and Methods 55 3.1 Materials................................... 55 3.1.1 Sadlermiut............................... 55 3.1.2 Point Hope.............................. 57 3.1.3 Kamarvik and Silumiut (Northwest Hudson Bay)......... 59 3.1.4 Greenland Thule and Inuit...................... 60 3.2 Sample selection................................ 60 3.3 Sex determination and age estimation.................... 61 3.3.1 Dental age intra-observer error.................... 62 3.3.2 Regression-based age estimation................... 62 3.4 Osteometric variables............................. 64 3.5 Investigation of linear growth........................ 67 3.6 Investigation of body proportion development............... 68 vi 4 Results 71 4.1 Sample composition.............................. 71 4.2 Investigation of linear growth........................ 75 4.2.1 Sadlermiut linear growth....................... 82 Summary............................... 88 4.2.2 Point Hope linear growth....................... 88 4.2.3 NW Hudson Bay and Greenland linear growth........... 91 4.2.4 Summary of growth analysis..................... 92 4.3 Investigation of body proportion development............... 95 4.3.1 Adult body proportions....................... 95 4.3.2 Sadlermiut body proportions..................... 106 4.3.3 Point Hope body proportions.................... 111 4.3.4 NW Hudson Bay and Greenland body proportions......... 115 4.3.5 Body proportion development summary and comparison..... 116 5 Discussion and Conclusions 120 5.1 Hypotheses.................................. 120 5.2 Linear growth................................. 121 5.3 Body proportion development........................ 125 5.4 Broader Implications............................. 126 5.5 Notes on limitations and unexplored data.................. 129 5.6 Conclusions.................................. 131 Bibliography 160 Appendix A Greenland Sample Information 161 Appendix B Dental Age Estimation 164 B.1 Dental age estimation examples....................... 164 vii B.2 Intra-observer error.............................. 164 B.3 Dental age regression............................. 165 Appendix C Additional Plots | Sample Distributions 171 Appendix D Additional Plots | Investigation of Growth 174 Appendix E Additional Plots | Investigation of Body Proportion Devel- opment 178 Appendix F Dataset 186 viii List of Tables 2.1 Historical Inuit infant mortality rates (IMR)................ 54 3.1 Osteometric variables............................. 65 3.2 Adult long bone end points (mm)...................... 67 3.3 Denver regression equations......................... 68 3.4 Body proportion indices........................... 69 3.5 Summary of comparative studies...................... 70 4.1 Number of juveniles per sample....................... 72 4.2 Number of adults per sample, by sex.................... 74 4.3 Adult brachial and crural index values................... 95 4.4 Comparative northern hemisphere body proportion samples, with latitude, brachial