Central Washington University ScholarWorks@CWU All Master's Theses Master's Theses Fall 2017 Enrichment Use & Social Interactions in a Mixed-Species Enclosure of Sumatran (Pongo abelij) & Bornean Orangutans (P. pygmaeus) & Northern White-Cheeked Gibbons (Nomascus leucogenys) Emily Veitia Central Washington University, [email protected] Follow this and additional works at: https://digitalcommons.cwu.edu/etd Part of the Animal Studies Commons, Behavior and Ethology Commons, Biological and Physical Anthropology Commons, Other Animal Sciences Commons, Other Ecology and Evolutionary Biology Commons, Other Social and Behavioral Sciences Commons, Terrestrial and Aquatic Ecology Commons, and the Zoology Commons Recommended Citation Veitia, Emily, "Enrichment Use & Social Interactions in a Mixed-Species Enclosure of Sumatran (Pongo abelij) & Bornean Orangutans (P. pygmaeus) & Northern White-Cheeked Gibbons (Nomascus leucogenys)" (2017). All Master's Theses. 910. https://digitalcommons.cwu.edu/etd/910 This Thesis is brought to you for free and open access by the Master's Theses at ScholarWorks@CWU. It has been accepted for inclusion in All Master's Theses by an authorized administrator of ScholarWorks@CWU. For more information, please contact [email protected]. ENRICHMENT USE & SOCIAL INTERACTIONS IN A MIXED-SPECIES ENCLOSURE OF SUMATRAN (Pongo abelii) & BORNEAN ORANGUTANS (P. pygmaeus) & NORTHERN WHITE-CHEEKED GIBBONS (Nomascus leucogenys) __________________________________ A Thesis Presented to the Graduate Faculty Central Washington University ___________________________________ In Partial Fulfillment of the Requirements for the Degree Master of Science Primate Behavior & Ecology ___________________________________ by Emily Sharai Veitia November 2017 CENTRAL WASHINGTON UNIVERSITY Graduate Studies We hereby approve the thesis of Emily Sharai Veitia Candidate for the degree of Master of Science APPROVED FOR THE GRADUATE FACULTY ______________ _________________________________________ Dr. Lori Sheeran, Committee Chair ______________ _________________________________________ Dr. Kara Gabriel, Committee Member ______________ _________________________________________ Karen Lewis, Committee Member ______________ _________________________________________ Dr. Kevin Archer, Dean of Graduate Studies i ABSTRACT ENRICHMENT USE & SOCIAL INTERACTIONS IN A MIXED-SPECIES ENCLOSURE OF SUMATRAN (Pongo abelii) & BORNEAN ORANGUTANS (P. pygmaeus) & NORTHERN WHITE-CHEEKED GIBBONS (Nomascus leucogenys) by Emily Sharai Veitia November 2017 Enrichment is an aspect of captive husbandry that has been shown to positively impact animals’ well-being and can be designed to encourage species-typical behaviors, such as foraging and arboreality. Enrichment can include housing together multiple compatible species. Orangutans are sympatric with siamangs and agile and Bornean gibbons, so several zoos house these four Asian ape species in the same enclosure, in part, as social enrichment. In my study, I observed enrichment use and social interactions in a mixed-species enclosure at the Oregon Zoo, which housed two Sumatran (Pongo abelii) and two Bornean (P. pygmaeus) orangutans with two Northern white-cheeked gibbons (Nomascus leucogenys). The study subjects were Bornean orangutans Kitra and Bob, Sumatran orangutans Kumar and Inji, and gibbons Phyllis and Duffy. From August 4-September 4, 2015, I conducted scan sampling every 30 seconds for 15-minute time blocks, totaling 82.5 hours and 9,911 scans. Using proportion tests, I tested whether each ape was equally likely to use arboreal and terrestrial enrichment. I predicted subjects would be more likely to use arboreal enrichment because of their arboreal natural histories. All individuals used arboreal enrichment significantly more than terrestrial enrichment. During my study, the two Sumatran orangutans and the two gibbons were ii housed together. I predicted that conspecifics would be more likely to interact than heterospecifics. Chi square tests supported this prediction. An additional component of my second hypothesis, which was conducted through descriptive statistics, was that interactions between conspecifics and heterospecifics would be more affiliative than aggressive. I found that heterospecifics and conspecifics had more affiliative instances (n = 1,750) than aggressive ones (n = 65). Keywords: Enrichment, Orangutans, Gibbons, Arboreal, Terrestrial iii ACKNOWLEDGMENTS First, I would like to thank the Oregon Zoo staff. Primate Zookeepers, Julia Walz, Scott Jackson, Colleen Reed, and Asaba Mukobi were essential in providing me with copious amounts of information and enrichment and food logs for the orangutans and gibbons. The zookeepers were always so helpful and accommodating during my time at the zoo. Karen Lewis, Conservation Research Associate, was also an integral part of this study. She has provided countless hours of help with my study, thesis and conferences that have resulted from it. This thesis would not have been possible without the incredible staff at the Oregon Zoo. I could not have asked for a better place to conduct my thesis research. Secondly, I would like to thank my advisor, Dr. Lori Sheeran for always being supportive and for dedicating an infinite number of hours to helping me with my Master’s thesis. Dr. Sheeran has encouraged me to take risks and continue my studies in Primatology and Biological Anthropology. She has the expertise, understanding, guidance and sense of humor that makes her an invaluable advisor. I have learned so much from her and I am eternally grateful to her for being my mentor, and the best mentor anyone could have, during my time here at CWU. I am very thankful to Central Washington University’s Institutional Animal Care and Use Committee for approving my study: Protocol number A051501. Additionally, this thesis was supported by the School of Graduate Studies and Research and by the Debra Prentice Scholarship for Primate Research. I am extremely grateful to have had Dr. Kara Gabriel on my committee. She gave me the support I needed when I couldn’t see the end of the tunnel. I could not have asked iv for a better person to review my statistical data and just give me advice. I am forever indebted to her. Thank you. I am immensely grateful to my husband for his support throughout my graduate career. Throughout the stress of pursuing this degree, he has always been my rock. I also want to thank my sister-in-law and friends for helping to provide an extra set of eyes when my own were so very tired. They have been my spelling and grammar check and thesaurus, and I could not have gotten through this without them. Finally, I am so thankful to my subjects: Inji, an old, curious, and human-centric soul who sought me out when she wanted to see what was inside my backpack; Kumar and Duffy, the best of friends and always willing to play and chase, despite being different species; Phyllis, the best ape I have ever met who showed me that gibbons are the best species of animals on this planet and who would come down to greet me every day; Bob, the “class clown”, who loved to show off his acrobatic skills to all visitors; and Kitra, who was very sweet and shy. Although they were just going about their daily business, they participated in my study and it would not have been possible without them. v TABLE OF CONTENTS Chapter Page I INTRODUCTION ........................................................................................ 1 II LITERATURE REVIEW ............................................................................. 4 Gibbons ................................................................................................... 4 Orangutans .............................................................................................. 5 Environmental Enrichment ..................................................................... 7 Naturalistic Enclosure ............................................................................. 9 Mixed-Species Enclosures .................................................................... 10 Red Ape Reserve ................................................................................... 13 III METHODS ................................................................................................. 17 Site......................................................................................................... 17 Subjects ................................................................................................. 17 Enrichment for subjects ......................................................................... 18 Data Collection ...................................................................................... 19 Data Classification ................................................................................ 20 IV RESULTS ................................................................................................... 22 Summary ............................................................................................... 22 Arboreal and Terrestrial Enrichment .................................................... 23 Social Interactions ................................................................................. 24 V DISCUSSION ............................................................................................. 26 Arboreal and Terrestrial Enrichment .................................................... 26 Social Interactions ................................................................................