Exploring the Endocrine Profile of a Geriatric Female Chimpanzee (Pan troglodytes) by Christina T. Cloutier A Thesis Submitted to the Faculty of The Dorothy F. Schmidt College of Arts and Letters in Partial Fulfillment of the Requirements for the Degree of Master of Arts Florida Atlantic University Boca Raton, FL May 2010 Copyright by Christina T. Cloutier 2010 ii ACKNOWLEDGEMENTS The author wishes to express her sincere thanks to a number of people involved in the writing of this manuscript, either indirectly or directly. First, thank you to the committee associated with this project, especially to Doctors Broadfield and Halloran for their invaluable advice and constructive criticisms throughout all of the phases of this project. The author is further grateful to Dr. Melissa Emery Thompson and the Hominoid Reproductive Ecology Laboratory at the University of New Mexico for the gracious guidance and assistance concerning the samples necessary for this project. Also, thank you to the chimpanzee keepers at Lion Country Safari during collection periods, for taking on the additional work load of having chimps in the house for months at a time. Finally, the author would like to thank her family for lending their support and encouragement throughout the entirety of this project. iv ABSTRACT Author: Christina Cloutier Title: Exploring the Endocrine Profile of a Geriatric Female Chimpanzee (Pan troglodytes) Thesis Advisor: Dr. Douglas C. Broadfield Degree: Master of Arts Year: 2010 In light of exceptionally delayed reproductive senescence exhibited by a 64 year old female chimpanzee (Pan troglodytes) housed in Florida, endocrinal analyses meant to determine the state of her current reproductive viability were conducted. Urine was collected from the study subject for a period of 88 days spaced within an interim of roughly 6 months and the specimens were sent to the Hominoid Reproductive Ecology Laboratory for assessment. Additional data was collected from three control females in order to provide a basis of comparison against the hormonal markers present in the geriatric study animal. Results indicate that the geriatric female does not presently appear to be cycling, but nor does she exhibit signs of complete reproductive cessation. This could signify that Pan troglodytes adheres to a pattern of reproductive aging not necessarily shared by Homo sapiens, which has further implications for the evolutionary trajectory of menopause in the human female. v DEDICATION To Mom and Dad, for being proud of me even though you still don’t know exactly what it is I do. To Chaz, for missing me while I’m away. And to Cindy, for quietly sitting close to me for no good reason at all. Exploring the Endocrine Profile of a Geriatric Female Chimpanzee (Pan troglodytes) List of Tables .................................................................................................................................. viii List of Figures .................................................................................................................................. ix The Great Biological Riddle ............................................................................................................. 1 Introduction………………………………………………………………………………………………1 Life History Theory ....................................................................................................................... 3 The Grandmother Hypothesis...................................................................................................... 3 An Alternative to the Grandmother Hypothesis ........................................................................... 5 Revisiting the Grandmother Hypothesis ...................................................................................... 6 The Physiological Phenomenon of Menopause .......................................................................... 8 An Early Understanding of the Biomechanics of Menopause ..................................................... 9 The Reproductive Cycles of Chimpanzees and Humans: ......................................................... 10 Exploring Alternative Models of Menopause: ............................................................................ 11 The Role of Somatic Aging in Female Reproductive Cessation ................................................ 13 A More Comprehensive Understanding of the Biomechanics of Menopause ........................... 14 Visual, Behavioral and Hormonal Markers of Reproduction in Pan troglodytes ........................ 16 The Great Debate: Does Pan troglodytes Undergo Complete Reproductive Cessation? ........ 20 The Contribution of Environmental Factors to Apparent Reproductive Stasis in Nonhuman Primates ..................................................................................................................................... 25 Monitoring the Endocrine Profile of a 72 Year Old Female Chimpanzee (Pan troglodytes ........... 29 The Significance of the Project .................................................................................................. 29 Contributions to Anthropological Theory ............................................................................... 33 Additional Contributions ........................................................................................................ 34 Methods ......................................................................................................................................... 39 The Reproductive Capacity of Pan troglodytes ......................................................................... 39 The Significance of Anogenital Tumescence in Female Chimpanzees (Pan troglodytes) ........ 40 Little Mama ................................................................................................................................ 42 Cindy .......................................................................................................................................... 45 Tonic .......................................................................................................................................... 47 Janice ......................................................................................................................................... 49 vi Lion Country Safari .................................................................................................................... 50 Data Collection .......................................................................................................................... 53 Statistical Methods ..................................................................................................................... 55 Implications for Reproductive Cessation in Nonhuman and Human Primates .............................. 58 Results ....................................................................................................................................... 58 Discussion.................................................................................................................................. 67 Summary.................................................................................................................................... 72 Future Studies ........................................................................................................................... 73 Appendix ........................................................................................................................................ 76 Bibliography ................................................................................................................................... 79 vii TABLES Table 2.1: Impact of Somatic Health on Chimpanzee Fertility Patterns in the Wild ................... 30 Table 2.2: Estimated number of robust (common) chimpanzee Pan troglodytes in 2003 by subspecies and country ................................................................................................................. 36 Table 2.3: Human Life Expectancy for both sexes (in years) ..................................................... 37 Table 3.1: The Reproductive History of Little Mama ................................................................... 45 Table 3.2: The Reproductive History of Cindy ............................................................................ 47 Table 3.3: The Reproductive History of Tonic ............................................................................ 48 Table 3.4: Chimpanzee Group Composition and Demographic at Lion Country Safari ............. 51 Table 4.1: Little Mama’s E1C Levels compared to those of the Control Group .......................... 60 Table 4.2: Little Mama’s PdG Levels compared to those of the Control Group ......................... 61 Table 4.3: Little Mama’s LH levels compared to those of the Control Group ............................. 61 Table 4.4: E1C (Little Mama vs. Cindy) ....................................................................................... 62 Table 4.5: PdG (Little Mama vs. Cindy) ...................................................................................... 63 Table 4.6: E1C (Little Mama vs. Tonic) ....................................................................................... 64 Table 4.7: PdG (Little Mama vs. Tonic) ...................................................................................... 64 Table 4.8: LH (Little Mama vs. Tonic) ........................................................................................