Abstract
The Asian apes, orangutans and gibbons, possess unusual social systems among anthropoid primates. Social groups of gibbons consist of mated adult pairs and their offspring; mature orangutans are primarily solitary. Recent experimental field research has begun to yield insights into the behavioral mechanisms employed by these animals to maintain their characteristic patterns of social dispersion. While spatial separation between female orangutans appears to be maintained passively, aggression, which is manifest during direct encounters and long-distance vocal interactions, mediates male asociality. Male-male aggression is the result of intense intrasexual competition occurring between animals for mating access to females. To reduce intrasexual competition, male orangutans have adopted alternative mating tactics. In contrast to female orangutans, female gibbons show marked agonistic tendencies toward conspecifics. Female territoriality contributes to preventing males from becoming polygynous. Male gibbons, restricted to monogamous relationships, attempt to ensure their paternity through intrasexual aggression. These observations suggest that the spatial dispersion of females constrains male mating options in both species. However, variations between orangutan and gibbon social systems can be understood as consequences of the temporal dispersion of sexually receptive females. The temporal clumping of females, due to relatively high operational sex ratios, limits the ability of male gibbons to acquire multiple mates. Conversely, an extremely low operational sex ratio in orangutans creates a strong selection pressure for intrasexual competition and polygamous mating. These considerations provide a novel framework for interpreting the social systems of the African apes.
Article PDF
Similar content being viewed by others
Avoid common mistakes on your manuscript.
References
Altmann, J. (1974). Observational study of behavior: Sampling methods.Behaviour 49: 227–267.
Bradbury, J., and Vehrencamp, S. (1977). Social organization and foraging in emballonurid bats. III. Mating systems.Behav. Ecol. Sociobiol. 2: 1–17.
Brockelman, W., and Srikosamatara, S. (1984). Maintenance and evolution of social structure in gibbons. In Prueschoft, H., Chivers, D., Brockelman, W., and Creel, N. (eds.),The Lesser Apes, Edinburgh University Press, Edinburgh, pp. 298–323.
Carpenter, C. R. (1940). A field study in Siam of the behavior and social relations of the gibbon (Hylobates lar).Comp. Psychol. Monogr. 16: 1–212.
Chivers, D. (1974).The Siamang in Malaya, Karger, Basel.
Crook, J., and Gartlan, S. (1966). Evolution of primate societies.Nature, Lond. 210: 1200–1203.
Darwin, C. (1871).Sexual Selection and the Descent of Man, John Murray, London.
Dunbar, R. (1987).Primate Social Systems, Croom Helm, London.
Emlen, S., and Orign, L. (1977). Ecology, sexual selection and the evolution of mating systems.Science 197: 215–223.
Galdikas, B. (1979). Orangutan adaptation at Tanjung Puting Reserve: Mating and ecology. In Hamburg, D., and McCown, E. (eds.),The Great Apes, Benjamin Cummings, Menlo Park, California, pp. 194–233.
Galdikas, B. (1982). Wild orangutan birth at Tanjung Puting Reserve.Primates 23: 500–510.
Galdikas, B. (1983). The orangutan long call and snag crashing at Tanjung Puting Reserve.Primates 24: 371–384.
Galdikas, B. (1984). Adult female sociality among wild orangutans at Tanjung Puting Reserve. In Small, M. (ed.),Female Primates: Studies by Women Primatologists, Liss, New York, pp. 217–235.
Galdikas, B. (1985a). Orangutan sociality at Tanjung Puting.Am J. Primatol. 9: 101–119.
Galdikas, B. (1985b). Subadult male orangutan sociality and reproductive behavior at Tanjung Puting.Am. J. Primatol. 8: 87–99.
Haimoff, E., Yang, X.-J., He, S.-J., and Chen, N. (1986). Census and survey of wild black-crested gibbons (Hylobates concolor concolor) in Yunnan Province, People's Republic of China.Folia Primatol. 46: 205–214.
Horr, D. A. (1975). The Borneo orangutan: Population structure and dynamics in relationship to ecology and reproductive strategy. In Rosenblum, L. (ed.),Primate Behavior: Developments in Field and Laboratory Research, Vol. 4, Academic Press, New York, pp. 307–323.
Lack, D. (1968).Ecological Adaptations for Breeding in Birds, Metheun, London.
Leighton, D. (1987). Gibbons: Territoriality and monogamy. In Smuts, B., Cheney, D., Seyfarth, R., Wrangham, R., and Struhsaker, T. (eds.),Primate Societies, University of Chicago Press, Chicago, pp. 135–145.
Lewontin, R. (1974).The Genetic Basis of Evolutionary Change, Columbia University Press, New York.
MacKinnon, J. (1971). The orangutan in Sabah today.Oryx 11: 141–191.
MacKinnon, J. (1974). The behaviour and ecology of wild orangutans (Pongo pygmaeus).Anim. Behav. 22: 3–74.
MacKinnon, J. (1979). Reproductive behavior in wild orangutan populations. In Hamburg, D., and McCown, E. (eds.),The Great Apes, Benjamin-Cummings, Menlo Park, California, pp. 256–273.
Marler, P. (1956). Territory and individual distance in the chaffinchFringilla coelebs. —Ibis: 98: 496–501.
Mitani, J. (1984). The behavioral regulation of monogamy in gibbons (Hylobates muelleri).Behav. Ecol. Sociobiol. 15: 225–229.
Mitani, J. (1985a). Mating behaviour of male orangutans in the Kutai Game Reserve, Indonesia.Anim. Behav. 33: 392–402.
Mitani, J. (1985b). Sexual selection and adult male orangutan long calls.Anim. Behav. 33: 272–283.
Mitani, J. (1985c). Gibbon song duets and intergroup spacingBehaviour 92: 59–96.
Mitani, J. (1987). Territoriality and monogamy among agile gibbons (Hylobates agilis).Behav. Ecol. Sociobiol. 20: 265–269.
Mitani, J. (1988). Male gibbon (Hylobates agilis) singing behavior: Natural history, song variations and function.Ethology 79: 177–194.
Nishida, T., and Hiraiwa-Hasegawa, M. (1987). Chimpanzees and bonobos: Cooperative relationships among males. In Smuts, B., Cheney, D., Seyfarth, R., Wrangham, R., and Struhsaker, T. (eds.),Primate Societies, University of Chicago Press, Chicago, pp. 165–177.
Raemaekers, J., Raemaeker, P. (1985). Field playback of loud calls to gibbons (Hylobates lar): Territorial, sex-specific and species-specific responses.Anim. Behav. 33: 481–493.
Robinson, S. (1986). The evolution of social behavior and mating systems in the blackbirds (Icterinae). In Rubenstein, D., and Wrangham, R. (eds.),Ecological Aspects of Social Evolution, Princeton University Press, Princeton, pp. 175–200.
Rodman, P. (1973). Population composition and adaptive organisation among orangutans of the Kutai Reserve. In Michael, R., and Crook, J. (eds.),Comparative Ecology and Behaviour of Primates. Academic Press, London, pp. 171–209.
Rodman, P. (1984). Foraging and social systems of orangutans and champanzees. In Rodman, P., and Cant, J. (eds.),Adaptations for Forating in Nonhuman Primates, Columbia University Press, New York, pp. 134–160.
Rodman, P., and Mitani, J. (1987). Orangutans: Sexual dimorphism in a solitary species. In Smuts, B., Cheney, D., Seyfarth, R., Wrangham, R., and Struhsaker, T. (eds.),Primate Societies, University of Chicago Press, Chicago, pp. 145–154.
Rubenstein, D. (1986). Ecology and sociality in horses and zebras. In Rubenstein, D., and Wrangham, R. (eds.),Ecological Aspects of Social Evolution, Princeton University Press, Princeton, pp. 282–302.
Rubenstein, D., and Wrangham, R. (1986).Ecological Aspects of Social Evolution, Princeton University Press, Princeton.
Schaller, G. (1961). The orangutan in Sarawak.Zoologica 46: 73–82.
Schurmann, C., and van Hooff, J. (1986). Reproductive strategies of the orangutan: New data and a reconsideration of existing socio-sexual models.Int. J. Primatol. 7:265–287.
Smuts, B., Cheney, D., Seyfarth, R., Wrangham, R., and Struhsaker, T. (1987).Primate Societies, University of Chicago Press, Chicago.
Snowdon, C. (1986). Vocal communication. In Mitchell, G., and Erwin, J. (eds.),Comparative Primate Biology, Vol. 2A, Liss, New York, pp. 495–530.
Srikosamatara, S., and Brockelman, W. (1987). Polygyny in a group of pileated gibbons via a familial route.Int. J. Primatol. 8: 389–393.
Tenaza, R. (1975). Territory and monogamy among Kloss' gibbons (Hylobates klossi) in Siberut Island, Indonesia.Folia Primatol. 24: 60–80.
Terborgh, J. (1983).Five New World Primates, Princeton University Press, Princeton.
Tinbergen, N. (1951).The Study of Instinct, Oxford University Press, Oxford.
Trivers, R. (1972). Parental investment and sexual selection. In Campbell, B. (ed.),Sexual Selection and the Descent of Man, Aldine, Chicago, pp. 136–179.
Tuttle, R. (1986).Apes of the World, Noyes Publications, Park Ridge, New Jersey.
van Schaik, C., and van Hooff J. (1983). On the ultimate causes of primate social systems.Behaviour 85: 91–117.
Waser, P., and Wiley, R. H. (1979). Mechanisms and evolution of spacing in animals. In Marler, P., and Vandenbergh, J. (eds.),Handbook of Behavioral Neurobiology, Vol. 3, Plenum, New York, pp. 159–223.
Wittenberger, J., and Tilson, R. (1980). The evolution of monogamy: Hypotheses and evidence.Ann. Rev. Ecol. Syst. 11: 197–232.
Wrangham, R. (1979). On the evolution of ape social systems.Soc. Sci. Inf. 18: 335–368.
Wrangham, R. (1980). An ecological model of female-bonded primate groups.Behaviour 75: 262–300.
Wrangham, R. (1986). Ecology and social relationships in two species of chimpanzees. In Rubenstein, D., and Wrangham, R. (eds.),Ecological Aspects of Social Evolution, Princeton University Press, Princeton, pp. 352–378.
Wrangham, R. (1987). Evolution of social structure. In Smuts, B., Cheney, D., Seyfarth, R., Wrangham, R., and Struhsaker, T. (1987).Primate Societies, University of Chicago Press., Chicago, pp. 282–296.
Yoshiba, K. (1964). Report of the preliminary survey on the orangutan in North Borneo.Primates 5: 11–26.
Zihlman, A., and Cramer, D. (1978). Skeletal differences between pygmy (Pan paniscus) and common chimpanzees (Pan troglodytes).Folia Primatol. 29: 86–94.
Author information
Authors and Affiliations
Rights and permissions
About this article
Cite this article
Mitani, J.C. Experimental field studies of Asian ape social systems. International Journal of Primatology 11, 103–126 (1990). https://doi.org/10.1007/BF02192784
Received:
Revised:
Issue Date:
DOI: https://doi.org/10.1007/BF02192784