Male orang-utan bimaturism and reproductive success at Camp Leakey in Tanjung Puting National Park, Indonesia
- 637 Downloads
Unlike most mammals, male orang-utans exhibit bimaturism, in that mature individuals express one of two distinct morphological forms. Socially subordinate, ‘unflanged’ males are comparable to females in their size and facial morphology, while socially dominant ‘flanged’ males exhibit extreme sexual dimorphism and secondary sexual characteristics, primarily in the form of cheek pads (‘flanges’). Although male ornaments in other species are often phenotypically plastic, such characteristics in orang-utans are irreversible—and, given that both morphs are sexually mature and can father offspring—their adaptive significance remains unclear. We determined paternity of orang-utans at Camp Leakey in Tanjung Puting National Park, within the home range of one long-term dominant male, Kusasi, before, during and after his period of dominance, in comparison with subordinate male conspecifics. We found that Kusasi fathered substantially more offspring conceived during his dominant period than any other male and that socially subordinate, unflanged males only fathered offspring during periods of rank instability. We conclude that orang-utan male bimaturism is consistent with an evolutionarily stable reproductive strategy and that reproduction within the range of a dominant, flanged male is highly skewed in his favour, while unflanged males may largely wait for reproductive opportunities.
KeywordsMale bimaturism Sexual selection Secondary sexual characteristics Paternity Reproductive success
We thank the Indonesian State Ministry of Research and Technology (RISTEK), the Indonesian State Ministry of Forestry (PHKA), the Indonesian Institute of Sciences (LIPI), the Indonesian Natural Resource Conservation Agency (BKSDA) and the Tanjung Puting National Park Office (BTNTP) for granting their permission to undertake this research and to our formal counterpart, S. H. Limin of CIMTROP at Universitas Palangka Raya, for his generous support of this work. We are indebted to A. E. Leiman OBE, S. Brend, P. A. Racey, S. B. Piertney and L. Howe who were instrumental to facilitating this research; to D. Rachmawan, J. R. Houslay, L. E. Koslowski, E. Tan and the Indonesian assistants who assisted with sample collection; to G. L. Shapiro, A. E. Russon and R. Garriga for their data on Kusasi’s history and to R. J. Turton, M. Arandjelovic and V. Städele for assistance with analyses. We thank the Los Angeles Zoo and Botanical Gardens, Como Park Zoo and Conservatory and Henry Vilas Zoo (all USA) for providing biomaterials from their orang-utans for use in developing the multiplex procedure, following approval by recommendation from the Orangutan Species Survival Plan (SSP). We are grateful for the comments of M. A. van Noordwijk and two anonymous reviewers, which greatly improved this manuscript.
This work was supported by the University of Aberdeen (UoA) Expedition Fund; UoA Small Grants Fund; UoA Alumni Annual Fund; the John Reid Trust; the Royal Geographical Society with Institute of British Geographers; the Royal Scottish Geographical Society; the Gilchrist Educational Trust; the Orangutan Foundation UK; the North of England Zoological Society at Chester Zoo; Darwin College, University of Cambridge; the Primate Society of Great Britain Charles A Lockwood Memorial Grant; the ARCUS Foundation; the Leverhulme Centre for Human Evolutionary Studies, University of Cambridge; the Miss Millie Foundation; Henry Vilas Zoo; The Orang-utan Conservation Genetics Trust and the Max Planck Society. GLB was supported by the Orang Utan Republik Foundation through the 2012 LP Jenkins Memorial Fellowship and by the German Academic Exchange Service (DAAD). The long-term research conducted at Camp Leakey, which facilitated this genetic study, was primarily funded by the Orangutan Foundation International.
Compliance with ethical standards
All applicable international, national and/or institutional guidelines for the care and use of animals were followed. Biological samples were exported from the Republic of Indonesia and from the United States of America to the European Union, via the United Kingdom, with permits 14459/IV/SATS-LN/2008, 00459/IV/SATS-LN/2011, 11US49805A/9 and 477248/01-27 under the Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES). All experiments described herein comply with the current laws of the countries in which they were performed. The authors declare that they have no conflict of interest.
- Alexander RD, Hoogland JL, Howard RD, Noonan KM, Sherman PW (1979) Sexual dimorphism and breeding systems in pinnipeds, ungulates, primates, and humans. In: Chagnon NA, Irons W (eds) Evolutionary biology and human social behavior: an anthropological perspective. Duxbury Press, North Scituate, pp 402–435Google Scholar
- Brandt EM, Mitchell G (1971) Parturition in primates: behavior related to birth. In: Rosenblum LA (ed) Primate behavior: developments in field and laboratory research, 2. Academic Press, New York, pp 178–223Google Scholar
- Galdikas BMF (1978) Orangutan adaptation at Tanjung Puting Reserve, Central Borneo. PhD thesis, University of California, Los AngelesGoogle Scholar
- Galdikas BMF (1981) Orangutan reproduction in the wild. In: Graham CE (ed) Reproductive Biology of the Great Apes. Academic Press, New York, pp 281–300Google Scholar
- Kingsley S (1982) Causes of non-breeding and the development of secondary sexual characteristics in the male orang-utan: a hormonal study. In: de Boer LM (ed) The orang-utan, its biology and conservation. Junk, Den Haag, pp 215–229Google Scholar
- Knott CD (2009) Orangutans: sexual coercion without sexual violence. In: Muller MN, Wrangham RW (eds) Sexual coercion in primates: an evolutionary perspective on male aggression against females. Harvard University Press, Cambridge, pp 81–111Google Scholar
- MacKinnon JR (1979) Reproductive behavior in wild orangutan populations. In: Hamburg DA, McCown ER (eds) The great apes. Benjamin/Cummings, Menlo Park, pp 256–273Google Scholar
- Porton I (1997) Birth control options. In: Sodaro C (ed) Orangutan species survival plan husbandry manual. Chicago Zoological Society, BrookfieldGoogle Scholar
- Rodman PS, Mitani JC (1987) Orangutans: sexual dimorphism in a solitary species. In: Smuts BB, Cheney DL, Seyfarth RM, Wrangham RW, Struhsaker TT (eds) Primate societies. University of Chicago Press, Chicago, pp 146–154Google Scholar
- Schürmann CL (1982) Mating behaviour of wild orang utans. In: de Boer LM (ed) The orang-utan, its biology and conservation. Junk, Den Haag, pp 269–284Google Scholar
- Short RV (1981) Sexual selection in man and the great apes. In: Graham CE (ed) Reproductive Biology of the Great Apes. Academic, London, pp 319–341Google Scholar
- Singleton I, Wich SA, Husson S, Stephens S, Utami-Atmoko SS, Leighton M, Rosen N, Traylor-Holzer K, Lacy R, Byers O (2004) Orangutan population and habitat viability assessment: final report. IUCN SSC Conservation Breeding Specialist Group, Apple ValleyGoogle Scholar
- Utami Atmoko SS, Mitra Setia T, Goossens B, James SS, Knott CD, Morrogh-Bernard HC, van Schaik CP, van Noordwijk MA (2009a) Orangutan mating behavior and strategies. In: Wich SA, Utami Atmoko SS, Mitra Setia T, van Schaik CP (eds) Orangutans: geographic variation in behavioral ecology and conservation. Oxford University Press, Oxford, pp 235–244Google Scholar
- Utami Atmoko SS, Singleton I, van Noordwijk MA, van Schaik CP, Mitra Setia T (2009b) Male-male relationships in orangutans. In: Wich SA, Utami Atmoko SS, Mitra Setia T, van Schaik CP (eds) Orangutans: geographic variation in behavioral ecology and conservation. Oxford University Press, Oxford, pp 225–234Google Scholar
- van Noordwijk MA, van Schaik CP (2004) Sexual selection and the careers of primate males: paternity concentration, dominance acquisition tactics and transfer decisions. In: Kappeler PM, van Schaik CP (eds) Sexual selection in primates: a comparative perspective. Cambridge University Press, Cambridge, pp 208–229CrossRefGoogle Scholar