The Oral Processing Behaviors of Mandrills (Mandrillus sphinx) in a Captive Setting Thesis Presented in Partial Fulfillment of the Requirements for the Degree Master of Arts in the Graduate School of The Ohio State University By Joseph Geherty Graduate Program in Anthropology The Ohio State University 2019 Thesis Committee W. Scott McGraw, Advisor Dawn Kitchen Jeffrey McKee 1 Copyrighted by Joseph Geherty 2019 2 Abstract Oral processing behaviors are known to co-vary with aspects of feeding ecology, food material properties, and cranio-dental anatomy. Previous field studies on terrestrial mangabeys (Cercocebus) have revealed important age/sex differences in the frequency of incision, isometric biting and chewing frequency related to diet. Here, I provide information on the Cercocebus sister taxon in order to better understand variation within this clade of African papionins. I examined oral processing behavior of captive mandrills (Mandrillus sphinx) at the Columbus Zoo and tested the hypothesis that extreme sexual dimorphism in this species would result in significant age and sex differences in food processing behaviors. I used focal animal sampling on an adult male and female, and two sub-adult males to quantify ingestive and oral processing behaviors associated with different foods made available to the monkeys. Kruskal-Wallis tests were performed on a sample of over 1,100 ingestive events across subjects. Significance tests revealed a variety of age/sex differences in rates of incision or mastication when individuals consumed the same food items. There was lack of a uniformity in mandrill oral processing behavior. There were certain foods the adult male used more incision or mastication but other foods in which the other individuals used more oral processing. Mandrill oral processing differs from sooty mangabey oral processing in which adult males had the highest number of incisions and mastications for hard object consumption iii than adult females or subadults. It is concluded that the extreme degree of sexual dimorphism of mandrills places a biomechanical constraint on oral processing behavior leading to an absence of differences of across ages and sexes. This conclusion needs to be tested further with additional data on free-ranging mandrills. iv Acknowledgments I am extremely grateful to The Ohio State University for providing me with the opportunity to conduct this research project. I would like to express my appreciation to Dr. W. Scott McGraw for introducing me to this project and helping me with my research and preparation of my thesis. I would also like to express my gratitude to Dr. Jeffrey McKee and Dr. Dawn Kitchen for serving as my Ohio State University committee members and the support I received from them. Lastly, I would like to thank the Columbus Zoo for allowing me the opportunity to study their mandrill group and for assisting me on my project. v Vita 2015………………………………………B.S. Anthropology, Biology, Psychology, University of New Mexico 2016………………………………………Field Research Assistant, Universidad Nacional Autónoma de México 2017 to present…………………………...Pursuing M.A. Anthropology, The Ohio State University Fields of Study Major Field: Anthropology vi Table of Contents Abstract .............................................................................................................................. iii Acknowledgments............................................................................................................... v Vita ..................................................................................................................................... vi List of Tables ................................................................................................................... viii List of Figures .................................................................................................................... ix Chapter 1. Introduction ....................................................................................................... 1 Cercocebus-Mandrillus relationship ............................................................................... 3 Cercocebus oral processing behaviors ............................................................................ 8 Mandrill diet.................................................................................................................. 10 Captive mandrills as a comparison ............................................................................... 13 Research Questions ....................................................................................................... 13 Chapter 2. Methods .......................................................................................................... 15 Subjects ......................................................................................................................... 15 Study site ....................................................................................................................... 16 Behavioral sampling methods ....................................................................................... 19 Data analysis ................................................................................................................. 22 Chapter 3. Results ............................................................................................................. 24 Diet ................................................................................................................................ 24 Comparison across food types ...................................................................................... 24 Comparison across age/sex class .................................................................................. 33 Chapter 4. Discussion ....................................................................................................... 39 General characteristics of mandrill processing activities.............................................. 40 Oral processing across age/sex classes ......................................................................... 41 The role of sexual dimorphism ..................................................................................... 42 Future directions ........................................................................................................... 45 Bibliography ..................................................................................................................... 47 vii List of Tables Table 1. Diet Composition ................................................................................................ 25 Table 2. P-values from Kruskal-Wallis tests that compare mean number of incisions for all eighteen foods: all individuals ..................................................................................... 27 Table 3. P-values from Kruskal-Wallis tests that compare mean number of mastications for all foods: all individuals .............................................................................................. 30 Table 4. P-values from Kruskal-Wallis comparisons of individuals for mature leaf incision .............................................................................................................................. 35 Table 5. P-values from Kruskal-Wallis comparisons of individuals for lettuce incision. 35 Table 6. P-values from Kruskal-Wallis comparisons of individuals for stem incision. ... 35 Table 7. P-values from Kruskal-Wallis comparisons of individuals for grass incision.... 35 Table 8. P-values from Kruskal-Wallis comparisons of individuals for insect incision. 35 Table 9. P-values from Kruskal-Wallis comparisons of individuals for ice cube incision. ........................................................................................................................................... 35 Table 10. P-values from Kruskal-Wallis comparisons of individuals for mature leaf mastication. ....................................................................................................................... 37 Table 11. P-values from Kruskal-Wallis comparisons of individuals for lettuce mastication. ....................................................................................................................... 37 Table 12. P-values from Kruskal-Wallis comparisons of individuals for stem mastication. ........................................................................................................................................... 37 Table 13. P-values from Kruskal-Wallis comparisons of individuals for grass mastication. ........................................................................................................................................... 37 Table 14. P-values from Kruskal-Wallis comparisons of individuals for insect mastication. ....................................................................................................................... 37 Table 15. P-values from Kruskal-Wallis comparisons of individuals for ice cube mastication. ....................................................................................................................... 37 viii List of Figures Figure 1. Cladograms depicting two possible organizations of Papionin ........................... 4 Figure 2. Adult male and female size comparison ............................................................ 16 Figure 3. View of mandrill exhibit from southern exposure ............................................ 18 Figure