Skip to main content
SpringerLink
Log in

Socioecological factors influencing population structure of gorillas and chimpanzees

  • Published:
Primates Aims and scope Submit manuscript

Abstract

Differences in distribution and density between gorillas and chimpanzees are reconsidered with special reference to population structure. Both ecological and social factors influencing population structure are compared between species and between habitats within species. Gorillas and chimpanzees respond differently to a decline in food quality, such as fruit scarcity: gorillas change diet and decrease range, while chimpanzees do not change diet but may expand range. These responses result in different effects on their grouping patterns. For gorillas the dispersed distribution and reduction of range size decreases the rate of inter-unit encounters and female transfer. The concentration of social units increases the rate of aggressive contact between units and stimulates female transfer. Social units of gorillas may crowd or disperse in order to attain the optimal density. This tendency may result in similar densities of gorillas across habitats. By contrast, the distribution patterns or range size may not affect inter-unit relationships of chimpanzees. Within a single unit-group, various reproductive strategies are adopted by both sexes. Independent travel of females and flexible grouping patterns enable them to survive at very low density in extraordinary large ranges. Density and inter-unit relationships are good criteria for a healthy population of gorillas, while the size of unit-group and inter-individual relationships are good criteria for chimpanzees. Conservation planners should consider these differences for sympatric and allopatric survival in these species.

This is a preview of subscription content, log in via an institution to check access.

Access this article

Log in via an institution

Price excludes VAT (USA)
Tax calculation will be finalised during checkout.

Instant access to the full article PDF.

Institutional subscriptions

Similar content being viewed by others

References

  • Aveling, C.;Harcourt, A. H. 1983. A census of the Virunga gorillas.Oryx, 18: 8–13.

    Article  Google Scholar 

  • Aveling, R.;Aveling, C. 1987. Report from the Zaire Gorilla Conservation Project.Primate Conserv., 8: 162–164.

    Google Scholar 

  • Baldwin, P. J.;McGrew, W. C.;Tutin, C. E. G. 1982. Wide-ranging chimpanzees at Mt. Assirik, Senegal.Int. J. Primatol., 3: 367–385.

    Google Scholar 

  • Basabose, K.;Yamagiwa, J. 1997. Predation on mammals by chimpanzees in the montane forest of Kahuzi, Zaire.Primates, 38: 45–55.

    Article  Google Scholar 

  • Blake, S.;Rogers, E.;Fay, J. M.;Ngangoue, M.;Ebeke, G. 1995. Swamp gorillas in northern Congo.Afr. J. Ecol., 33: 285–290.

    Google Scholar 

  • Boesch, C. 1991. The effect of leopard predation on grouping patterns in forest chimpanzees.Behaviour, 117: 220–241.

    Google Scholar 

  • Boesch, C. 1996. Social grouping in Tai chimpanzees. In:Great Ape Societies,McGrew,W. C.;Marchant,L. F.;Nishida,T. (eds.), Cambridge Univ. Press, Cambridge, pp. 101–113.

    Google Scholar 

  • Boesch, C.;Boesch, H. 1984. Possible cause of sex differences in the use of natural hummers by wild chimpanzees.J. Human Evol., 13: 415–440.

    Article  Google Scholar 

  • Boesch, C.;Boesch, H. 1989. Hunting behavior of wild chimpanzees in the Tai National Park.Amer. J. Phys. Anthropol., 78: 547–573.

    Article  CAS  Google Scholar 

  • Butynski, T. 1992. Institute of tropical forest conservation—Uganda (former Impenetrable Forest Conservation Project).Gorilla Conserv. News 6: 25–28.

    Google Scholar 

  • Carroll, R. W. 1986. Status of the lowland gorilla and other wildlife in the Dzanga-Sangha region of southwestern Central African Republic.Primate Conserv., 7: 38–41.

    Google Scholar 

  • Carroll, R. W. 1988. Relative density, range extension, and conservation potential of the lowland gorilla (Gorilla gorilla gorilla) in the Dzanga-Sangha region of southwestern Central African Republic.Mammalia, 52: 309–323.

    Google Scholar 

  • Casimir, M. J.;Butenandt, E. 1973. Migration and core area shifting in relation to some ecological factors in a mountain gorilla group (Gorilla gorilla beringei) in the Mt. Kahuzi region (République du Zaire).Z. Tierpsychol., 33: 514–522.

    Google Scholar 

  • Chapman, C. A.;White, F. J.;Wrangham, R. W. 1994. Party size in chimpanzees and bonobos. In:Chimpanzee Cultures.Wrangham, R. W.;McGrew, W. C.;de Waal, F. B. M.;Heltne, P. G. (eds.), Harvard Univ. Press, Cambridge, Massachusetts, pp. 41–57.

    Google Scholar 

  • Cheney, D. L. 1977. The acquisition of rank and the development of reciprocal alliances among free-ranging immature baboons.Behav. Ecol. Sociobiol., 2: 303–318.

    Article  Google Scholar 

  • Clutton-Brock, T. H. (ed.). 1977. Some aspects of intraspecific variation in feeding and ranging behaviour in primates. In:Primate Ecology, Academic Press, London, pp. 539–556.

    Google Scholar 

  • Datta, S. B. 1989. Demographic influences on dominance structure among female primates. In:Comparative Socioecology,Standen,V.;Foley,R. A. (eds.), Blackwell, Oxford pp. 265–284.

    Google Scholar 

  • Elliott, R. C. 1976. Observations on a small group of mountain gorillas (Gorilla gorilla beringei).Folia Primatol., 25: 12–24.

    PubMed  CAS  Google Scholar 

  • Fay, M. J.;Agnagna, M. 1992. Census of gorillas in northern Republic of Congo.Amer. J. Primatol., 27: 275–284.

    Article  Google Scholar 

  • Fay, M. J.;Agnagna, M.;Moore, J.;Oko, R. 1989. Gorillas in the Likouala swamp forest of north central Congo.Int. J. Primatol., 10: 477–486.

    Google Scholar 

  • Fossey, D. 1982. Reproduction among free-living mountain gorillas.Amer. J. Primatol. (Suppl.), 1: 97–104.

    Article  Google Scholar 

  • Fossey, D. 1983.Gorillas in the Mist. Houghton Mifflin, Boston.

    Google Scholar 

  • Fossey, D. 1984. Infanticide in mountain gorillas (Gorilla gorilla beringei) with comparative notes on chimpanzees. In:Infanticide: Comparative and Evolutionary Perspectives,Hausfater,G.;Hrdy,S. B. (eds.), Aldine, Hawthorne, New York, pp. 217–236.

    Google Scholar 

  • Fossey, D.;Harcourt, A. H. 1977. Feeding ecology of free-ranging mountain gorilla (Gorilla gorilla beringei). In:Primate Ecology,Clutton-Brock,T. H. (ed.), Academic Press, New York, pp. 415–447.

    Google Scholar 

  • Furuichi, T. 1989. Social interactions and the life history of femalePan paniscus in Wamba, Zaire.Int. J. Primatol., 10: 173–197.

    Google Scholar 

  • Ghiglieri, M. P. 1984.The Chimpanzees of Kibale Forest: A Field Study of Ecology and Social Structure. Columbia Univ. Press, New York.

    Google Scholar 

  • Goodall, A. G. 1977. Feeding and ranging behavior of a mountain gorilla group (Gorilla gorilla beringei) in the Tshibinda-Kahuzi region (Zaire). In:Primate Ecology,Clutton-Brock,T. H. (ed.), Academic Press, New York, pp. 450–479.

    Google Scholar 

  • Goodall, J. 1968. Behaviour of free-living chimpanzees of the Gombe Stream Reserve.Anim. Behav. Monogr., 1: 161–311.

    Google Scholar 

  • Goodall, J. 1977. Infant killing and cannibalism in free-living chimpanzees.Folia Primatol. 28: 259–282.

    PubMed  CAS  Google Scholar 

  • Goodall, J. 1986.The Chimpanzees of Gombe. Belknap, Cambridge.

    Google Scholar 

  • Goodall, J. 1990.Through a Window: Thirty Years with the Chimpanzees of Gombe. Soko Publ., London.

    Google Scholar 

  • Goodall, J.;Bandora, A.;Bergmann, E.;Busse, C.;Matama, H.;Mpongo, E.;Pierce, A.;Riss, D. 1979. Intercommunity interactions in the chimpanzee population of the Gombe National Park. In:The Great Apes,Hamburg,D. A.;McCown,E. R. (eds.), Benjamin/Cummings, Menlo Park, pp. 13–53.

    Google Scholar 

  • Groves, C. P. 1971. Distribution and place of origin of the gorilla.Man, 6: 44–51.

    Article  Google Scholar 

  • Hall, J. S.;White, L. J.;Inogwabini, B-I.;Omari, I.;Morland, H. S.;Williamson, E. A.;Saltonstall, K.;Walsh, P.;Sikubwabo, C.;Bonny, D.;Kaleme, K. P.;Vedder, A.;Freeman, K. 1998. A survey of Grauer's gorillas (Gorilla gorilla graueri) and chimpanzees (Pan troglodytes schweinfurthii) in the Kahuzi-Biega National Park lowland sector and adjacent forest in eastern Congo.Int. J. Primatol., 19: 207–235.

    Article  Google Scholar 

  • Hamai, M.;Nishida, T.;Takasaki, H.;Turner, L. A. 1992. New records of within-group infanticide and cannibalism in wild chimpanzees.Primates, 33: 151–162.

    Article  Google Scholar 

  • Harcourt, A. H. 1978. Strategies of emigration and transfer by primates, with particular reference to gorillas.Z. Tierpsychol., 48: 401–420.

    PubMed  CAS  Google Scholar 

  • Harcourt, A. H. 1981. Can Uganda's gorillas survive?: a survey of the Bwindi Forest Reserve.Biol. Conserv., 19: 269–282.

    Article  Google Scholar 

  • Harcourt, A. H. 1996. Is the gorilla a threatened species?: How should we judge?.Biol. Conserv., 75: 165–176.

    Article  Google Scholar 

  • Harcourt, A. H.;Fossey, D. 1981. The Virunga gorillas: decline of an ‘island’ population.Afr. J. Ecol., 19: 83–97.

    Google Scholar 

  • Harcourt, A. H.;Fossey, D.;Sabater Pi, J. 1981. Demography ofGorilla gorilla.J. Zool., Lond., 195: 215–233.

    Article  Google Scholar 

  • Harcourt, A. H.;Stewart, K. J. 1989. Functions of alliances in contests within gorilla groups.Behaviour, 109: 176–190.

    Google Scholar 

  • Harcourt, A. H.;Stewart, K. J.;Fossey, D. 1976. Male emigration and female transfer in wild mountain gorillas.Nature, Lond., 263: 226–227.

    Article  Google Scholar 

  • Hasegawa, T.;Hiraiwa-Hasegawa, M. 1983. Opportunistic and restrictive mating among wild chimpanzees in the Mahale Mountains, Tanzania.J. Ethol., 1: 75–85.

    Article  Google Scholar 

  • Hashimoto, C. 1993. Ecological survey on chimpanzees in the Kalinzu forest, Uganda: a preliminary report.Primate Res., 9: 113–118, (in Japanese with English summary)

    Article  Google Scholar 

  • Hoppe-Dominik, B. 1991. Distribution and status of chimpanzees (Pan troglodytes verus) on the Ivory Coast.Primate Rep., 31 (October): 45–75.

    Google Scholar 

  • Idani, G. 1990. Relations between unit-groups of bonobos at Wamba, Zaire: encounters and temporary fusions.Afr. Stu. Monogr., 11: 153–186.

    Google Scholar 

  • Ihobe, H. 1993. A preliminary study on distribution of chimpanzees in Region de Niari and Lekoumou, Congo.Primate Res., 9: 119–124. (in Japanese with English summary)

    Article  Google Scholar 

  • Itani, J. 1977. Evolution of primate social structure.J. Human Evol., 6: 235–243.

    Article  Google Scholar 

  • Itani, J. 1980. Social structure of African great apes.J. Reprod. Fertil. (Suppl.), 28: 33–41.

    Google Scholar 

  • Itani, J.;Suzuki, A. 1967. The social unit of chimpanzees.Primates, 8: 355–381.

    Article  Google Scholar 

  • Izawa, K. 1970. Unit groups of chimpanzees and their nomadism in the savanna woodland.Primates, 11: 1–45.

    Article  Google Scholar 

  • Jones, C.;Sabater Pi, J. 1971. Comparative ecology ofGorilla gorilla (Savage andWyman) andPan troglodytes (Blumenbach) in Rio Muni, West Africa.Bibl. Primatol., 13: 1–96.

    Google Scholar 

  • Kano, T. 1971. The chimpanzee of Filabanga, Western Tanzania.Primates, 12: 229–246.

    Article  Google Scholar 

  • Kano, T. 1972. Distribution and adaptation of the chimpanzee on the eastern shore of Lake Tanganyika.Kyoto Univ. Afr. Stu., 7: 37–129.

    Google Scholar 

  • Kano, T. 1986.The Last Ape: Pygmy Chimpanzee Behavior and Ecology. Stanford Univ. Press, Stanford.

    Google Scholar 

  • Kano, T.;Asato, R. 1994. Hunting pressure on chimpanzees and gorillas in the Motaba River area, northeastern Congo.Afr. Stu. Monogr., 15: 143–162.

    Google Scholar 

  • Kawanaka, K. 1981. Infanticide and cannibalism in chimpanzees with special reference to the newly observed case in the Mahale Mountains.Afr. Stu. Monogr., 1: 69–99.

    Google Scholar 

  • Kuroda, S.;Nishihara, T.;Suzuki, S.;Oko, R. A. 1996. Sympatric chimpanzees and gorillas in the Ndoki Forest, Congo. In:Great Ape Societies,McGrew,W. C.;Marchant,L. F.;Nishida,T. (eds.), Cambridge Univ. Press, Cambridge, pp. 71–81.

    Google Scholar 

  • McGrew, W. C. 1992.Chimpanzee Material Culture: Implications for Human Evolution. Cambridge Univ. Press, Cambridge.

    Google Scholar 

  • McGrew, W. C.;Baldwin, P. J.;Tutin, C. E. G. 1981. Chimpanzees in a hot, dry and open habitat: Mt. Assirik, Senegal, West Africa.J. Human Evol., 10: 227–244.

    Google Scholar 

  • Mitani, M. 1992. Preliminary results of the studies on wild western lowland gorillas and other sympatric diurnal primates in the Ndoki Forest, northern Congo. In:Topics in Primatology, Vol. 2: Behavior, Ecology and Conservation,Itoigawa,N.;Sugiyama,Y.;Sackett,G. P.;Thompson,R. K. R. (eds.), Univ. of Tokyo Press, Tokyo, pp. 215–224.

    Google Scholar 

  • Moore, J. 1992. “Savanna” chimpanzees. In:Topics in Primatology, Vol. 1: Human Origins,Nishida,T.;McGrew,W. C.;Maller,P.;Pickford,M.;de Waal,F. B. M. (eds.), Univ. of Tokyo Press, Tokyo, pp. 99–118.

    Google Scholar 

  • Moore, J. 1996. Savanna chimpanzees, referential models and the last common ancestor. In:Great Ape Societies,McGrew,W. C.;Marchant,L. F.;Nishida,T. (eds.), Cambridge Univ. Press, Cambridge, pp. 275–292.

    Google Scholar 

  • Murnyak, D. F. 1981. Censusing gorillas in Kahuzi-Biega National Park.Biol. Conserv., 21: 247–340.

    Article  Google Scholar 

  • Nishida, T. 1968. The social group of wild chimpanzees in the Mahali Mountains.Primates, 9: 167–224.

    Article  Google Scholar 

  • Nishida, T. 1974. Ecology of wild chimpanzees. In:Human Ecology,Ohtsuka,R.;Tanaka,J.;Nishida,T. (eds.), Kyoritsu-shuppan, Tokyo, pp. 15–60 (in Japanese)

    Google Scholar 

  • Nishida, T. 1979. The social structure of chimpanzees of the Mahale Mountains. In:The Great Apes,Hamburg,D. A.;McCown,E. R. (eds.), Benjamin/Cummings, Menlo Park, California, pp. 73–121.

    Google Scholar 

  • Nishida, T. 1983. Alpha status and agonistic alliance in wild chimpanzees (Pan troglodytes schweinfurthii).Primates, 24: 318–336.

    Article  Google Scholar 

  • Nishida, T.;Hiraiwa-Hasegawa, M. 1987. Chimpanzees and bonobos: cooperative relationships among males. In:Primate Societies,Smuts,B. B.;Wrangham,R. W.;Cheney,D. L.;Struhsaker,T. T.;Seyfarth,R. M. (eds.), Univ. of Chicago Press, Chicago, pp. 165–177.

    Google Scholar 

  • Nishida, T.;Hiraiwa-Hasegawa, M.;Hasegawa, T.;Takahata, Y. 1985. Group extinction and female transfer in wild chimpanzees in the Mahale Mountains.Z. Tierpsychol., 67: 284–301.

    Google Scholar 

  • Nishida, T.;Kawanaka, K. 1972. Inter-unit-group relationships among wild chimpanzees of the Mahali Mountains.Kyoto Univ. Afr. Stu., 7: 131–169.

    Google Scholar 

  • Nishida, T.;Uehara, S. 1983. Natural diet of chimpanzees (Pan troglodytes schweinfurthii): long-term record from the Mahale Mountains, Tanzania.Afr. Stu. Monogr., 3: 109–130.

    Google Scholar 

  • Nishihara, T. 1994. Population density and group organization of gorillas (Gorilla gorilla gorilla) in the Nouabale-Ndoki National Park, Congo.Africa Kenkyu (J. Afr. Stu.), 44: 29–45. (in Japanese with English abstract)

    Google Scholar 

  • Nishihara, T. 1995. Feeding ecology of western lowland gorillas in the Nouabalé-Ndoki National Park, Congo.Primates, 36: 151–168.

    Article  Google Scholar 

  • Oates, J. F. 1987. Food distribution and foraging behavior. In:Primate Societies,Smuts,B. B.;Wrangham,R. W.;Cheney,D. L.;Struhsaker,T. T.;Seyfarth,R. M. (eds.), Univ. of Chicago Press, Chicago, pp. 197–209.

    Google Scholar 

  • Ogawa, H. 1997. The discovery of chimpanzees in the Lwazi River area, Tanzania: a new southern distribution limit.Pan Afr. News, 4(1): 1–3.

    Google Scholar 

  • Remis, M. J. 1993. Nesting behavior of lowland gorillas in the Dzanga-Sangha Reserve, Central African Republic: implications for population estimates and understandings of group dynamics.Tropics, 2: 245–255.

    Article  Google Scholar 

  • Remis, M. J. 1994. Feeding ecology and positional behavior of western lowland gorillas (Gorilla gorilla gorilla) in the Central African Republic. Ph.D. thesis, Yale Univ., Yale.

    Google Scholar 

  • Reynolds, V.;Reynolds, F. 1965. Chimpanzees of the Budongo Forest. In:Primate Behavior,DeVore,I. (ed.), Holt, Rinehart & Winston, New York, pp. 368–424.

    Google Scholar 

  • Robbins, M. M. 1995. A demographic analysis of male life history and social structure of mountain gorillas.Behaviour, 132: 21–48.

    Google Scholar 

  • Sakura, O. 1994. Factors affecting party size and composition of chimpanzees (Pan troglodytes verus) at Bossou, Guinea.Int. J. Primatol., 15: 167–183.

    Google Scholar 

  • Sarich, V. M.;Cronin, J. E. 1977. Generation length and rates of hominoid molecular evolution.Nature, 269: 354.

    Article  PubMed  CAS  Google Scholar 

  • Schaller, G. B. 1963.The Mountain Gorilla: Ecology and Behavior, Univ. of Chicago Press, Chicago.

    Google Scholar 

  • Schoener, T. W. 1971. Theory of feeding strategies.Anim. Rev. Ecol. Syst., 2: 369–404.

    Article  Google Scholar 

  • Shea, B. T. 1983. Size and diet in the evolution of African ape craniodental form.Folia Primatol., 40: 32–68.

    PubMed  CAS  Google Scholar 

  • Sicotte, P. 1993. Inter-group interactions and female transfer in mountain gorillas: influence of group composition on male behavior.Amer. J. Primatol., 30: 21–36.

    Article  Google Scholar 

  • Sicotte, P. 1995. Interpositions in conflicts between males in bimale groups of mountain gorillas.Folia Primatol., 65: 14–24.

    PubMed  CAS  Google Scholar 

  • Stanford, C.;Wallis, J.;Mpongo, E.;Goodall, J. 1994. Hunting decisions in wild chimpanzees.Behaviour, 131: 1–18.

    Google Scholar 

  • Sugiyama, Y. 1969. Social behavior of chimpanzees in the Budongo Forest, Uganda.Primates, 10: 197–225.

    Article  Google Scholar 

  • Sugiyama, Y. 1981. Observations on the population dynamics and behavior of wild chimpanzees at Bossou, Guinea, in 1979–1980.Primates, 22: 435–444.

    Article  Google Scholar 

  • Sugiyama, Y.;Koman, J. 1979. Social structure and dynamics of wild chimpanzees at Bossou, Guinea.Primates, 20: 323–339.

    Article  Google Scholar 

  • Sugiyama, Y.;Koman, J. 1987. A preliminary list of chimpanzees' alimentation at Bossou, Guinea.Primates, 28: 133–147.

    Article  Google Scholar 

  • Suzuki, A. 1969. An ecological study of chimpanzees in a savanna woodland.Primates, 10: 103–148.

    Article  Google Scholar 

  • Suzuki, S. 1993. Preliminary results of the studies on tschego chimpanzees (Pan t. troglodytes) in the Ndoki Forest Congo. In:Comparative Socio-ecological Study of Sympatric Tschego Chimpanzees and Western Lowland Gorillas: A Grant under the Monbusho International Scientific Research Report, pp. 19–24.

  • Takahata, Y. 1985. Adult male chimpanzees kill and eat a male newborn infant: newly observed intragroup infanticide and cannibalism in Mahale National Park, Tanzania.Folia Primatol., 44: 121–128.

    Article  Google Scholar 

  • Tutin, C. E. G. 1979. Mating patterns and reproductive strategies in a community of wild chimpanzees (Pan troglodytes schweinfurthii).Behav. Ecol. Sociobiol., 6: 29–38.

    Article  Google Scholar 

  • Tutin, C. E. G. 1996. Ranging and social structure of lowland gorillas in the Lopé Reserve, Gabon. In:Great Ape Societies,McGrew,W. C.;Marchant,L. F.;Nishida,T. (eds), Cambridge Univ. Press, Cambridge, pp. 58–70.

    Google Scholar 

  • Tutin, C. E. G.;Fernandez, M. 1984. Nationwide census of gorilla (Gorilla g. gorilla) and chimpanzee (Pan t. troglodytes) populations in Gabon.Amer. J. Primatol., 6: 313–336.

    Article  Google Scholar 

  • Tutin, C. E. G.;Fernandez, M. 1992. Insect-eating by sympatric lowland gorillas (Gorilla g. gorilla) and chimpanzees (Pan t. troglodytes) in the Lopé Reserve, Gabon.Amer. J. Primatol., 28: 29–40.

    Article  Google Scholar 

  • Tutin, C. E. G.;Fernandez, M. 1993. Composition of the diet of chimpanzees and comparisons with that of sympatric lowland gorillas in the Lopé Reserve, Gabon.Amer. J. Primatol., 30: 195–211.

    Article  Google Scholar 

  • Tutin, C. E. G.;Fernandez, M.;Rogers, M. E.;Williamson, E. A. 1992. A preliminary analysis of the social structure of lowland gorillas in the Lopé Reserve, Gabon. In:Topics in Primatology, Vol. 2: Behavior, Ecology, and Conservation,Itoigawa,N.;Sugiyama,Y.;Sackett,G. P.;Thompson,R. K. R. (eds.), Univ. of Tokyo Press, Tokyo, pp. 245–254.

    Google Scholar 

  • Tutin, C. E. G.;McGinnis, P. R. 1981. Chimpanzee reproduction in the wild. In:Reproductive Biology of the Great Apes: Comparative and Biomedical Perspective,Graham,C. E. (ed.), Academic Press, New York, pp. 239–264.

    Google Scholar 

  • Tutin, C. E. G.;McGrew, W. C.;Baldwin, P. J. 1983. Social organization of savanna-dwelling chimpanzees,Pan troglodytes verus, at Mt. Assirik, Senegal.Primates 24: 154–173.

    Article  Google Scholar 

  • Tutin, C. E. G.;Parnell, R. J.;White, L. J. T.;Fernandez, M. 1995. Nest building by lowland gorillas in the Lopé Reserve, Gabon: environmental influences and implications for censusing.Int. J. Primatol., 16: 53–76.

    Google Scholar 

  • Uehara, S. 1981. The social unit of wild chimpanzees: a reconsideration based on the diachronic data accumulated at Kasoje in the Mahale Mountains, Tanzania.Africa Kenkyu (J. Afr. Stu.), 20: 15–32. (in Japanese with English summary)

    Google Scholar 

  • Uehara, S. 1986. Sex and group differences in feeding on animals by wild chimpanzees in the Mahale Mountains National Park, Tanzania.Primates, 27: 1–13.

    Article  Google Scholar 

  • Uehara, S.;Nishida, T.;Takasaki, H.;Kitopeni, R.;Kasagula, B. M.;Norikoshi, K.;Tsukahara, T.;Nyundo, R.;Hamai, M. 1994. A lone male chimpanzee in the wild: the survivor of a disintegrated unit-group.Primates, 35: 275–281.

    Article  Google Scholar 

  • de Waal, F. B. M. 1989.Peacemaking Among Primates. Harvard Univ. Press, Cambridge, Massachusett.

    Google Scholar 

  • Watanabe, K. 1979. Alliance formation in a free-ranging troop of Japanese macaques.Primates, 20: 459–474.

    Article  Google Scholar 

  • Watts, D. P. 1984. Composition and variability of mountain gorilla diets in the Central Virungas.Amer. J. Primatol., 7: 323–356.

    Article  Google Scholar 

  • Watts, D. P. 1989. Infanticide in mountain gorillas: new cases and a reconsideration of the evidence.Ethology, 81: 1–18.

    Article  Google Scholar 

  • Watts, D. P. 1990. Ecology of gorillas and its relationship to female transfer in mountain gorillas.Int. J. Primatol., 11: 21–45.

    Article  Google Scholar 

  • Watts, D. P. 1991. Strategies of habitat use by mountain gorillas.Folia Primatol., 56: 1–16.

    Article  PubMed  CAS  Google Scholar 

  • Watts, D. P. 1992. Social relationships of resident and immigrant female mountain gorillas, I: Male female relationships.Amer. J. Primatol., 28: 159–181.

    Article  Google Scholar 

  • Watts, D. P. 1997. Agonistic interventions in wild mountain gorilla groups.Behaviour, 134: 23–57.

    Google Scholar 

  • Weber, A. W.;Vedder, A. 1983. Population dynamics of the Virunga gorillas: 1959–1978.Biol. Conserv., 26: 341–366.

    Article  Google Scholar 

  • White, L. J. T. 1994. Biomass of rain forest mammals in the Lopé Reserve, Gabon.J. Anim. Ecol., 63: 499–512.

    Article  Google Scholar 

  • Williamson, E. A. 1988. Behavioral ecology of western lowland gorillas in Gabon. Ph.D. thesis, Univ. of Stirling, Stirling.

    Google Scholar 

  • Wolfheim, J. H. 1983.Primate of the World: Distribution, Abundance, and Conservation. Univ. of Washington Press, Seattle & London.

    Google Scholar 

  • Wrangham, R. W. 1975. The behavioral ecology of chimpanzees in the Gombe National Park, Tanzania. Ph.D. thesis, Cambridge Univ., Cambridge.

    Google Scholar 

  • Wrangham, R. W. 1977. Feeding behaviour of chimpanzees in Gombe National Park, Tanzania. In:Primate Ecology,Clutton-Brock,T. H. (ed.), Academic Press, London, pp. 503–537.

    Google Scholar 

  • Wrangham, R. W. 1979. Sex differences in chimpanzee dispersion. In:The Great Apes,Hamburg,D. A.;McCown,E. R. (eds.), Benjamin/Cummings, Menlo Park, pp. 480–489.

    Google Scholar 

  • Wrangham, R. W. 1980. An ecological model of female-bonded primate groups.Behaviour 75: 262–300.

    Google Scholar 

  • Wrangham, R. W. 1986. Ecology and social relationships in two species of chimpanzees. In:Ecological Aspects of Social Evolution: Birds and Mammals,Rubenstein,D. I.;Wrangham,R. W. (eds.), Princeton Univ. Press, Princeton, pp. 352–378.

    Google Scholar 

  • Wrangham, R. W. 1987. Evolution of social structure. In:Primate Societies,Smuts,B. B.;Wrangham,R. W.;Cheney,D. L.;Struhsaker,T. T.;Seyfarth,R. M. (eds.), Univ. of Chicago Press, Chicato, pp. 282–296.

    Google Scholar 

  • Wrangham, R. W.;Chapman, C. A.;Clark-Arcadi, A. P.;Isabirye-Basuta, G. 1996. Social ecology of Kanyawara chimpanzees: implications for understanding the costs of great ape groups. In:Great Ape Societies,McGrew,W. C.;Marchant,L. F.;Nishida,T. (eds.), Cambridge Univ. Press, Cambridge, pp. 45–57.

    Google Scholar 

  • Wrangham, R. W.;Smuts, B. B. 1980. Sex differences in behavioural ecology of chimpanzees in Gombe National Park, Tanzania.J. Reprod. Fertil. (Suppl.), 28: 13–31.

    Google Scholar 

  • Yamagiwa, J. 1983. Diachronic changes in two eastern lowland gorilla groups (Gorilla gorilla graueri) in the Mt. Kahuzi Region, Zaïre.Primates, 24: 174–183.

    Article  Google Scholar 

  • Yamagiwa, J. 1986. Activity rhythm and the ranging of a solitary male mountain gorilla (Gorilla gorilla beringei).Primates, 27: 273–282.

    Article  Google Scholar 

  • Yamagiwa, J. 1987a. Intra- and inter-group interactions of an all-male group of Virunga mountain gorillas (Gorilla gorilla beringei).Primates, 28: 1–30.

    Article  Google Scholar 

  • Yamagiwa, J. 1987b. Male life history and social structure of wild mountain gorillas (Gorilla gorilla beringei). In:Evolution and Coadaptation in Biotic Communities,Kawano,S.;Connell,J. H.;Hidaka,T. (eds.), Univ. of Tokyo Press, Tokyo, pp. 31–51.

    Google Scholar 

  • Yamagiwa, J.;Angoue-Ovono, S.;Kasisi, R. 1995. Densities of apes' food trees and primates in the Petit Loango Reserve, Gabon.Afr. Stu. Monogr., 16: 181–193.

    Google Scholar 

  • Yamagiwa, J.; Maruhashi, T.; Yumoto, Y.; Mwanza, N. 1989. A preliminary survey on sympatric populations ofGorilla g. graueri andPan t. schweinfurthii in eastern Zaire. In:Grant-in Aid for Overseas Scientific Research Report: Interspecies Relationships of Primates in the Tropica and Montane Forests 1, pp. 23–40.

  • Yamagiwa, J.;Maruhashi, T.;Yumoto, T.;Mwanza, N. 1996. Dietary and ranging overlap in sympatric gorillas and chimpanzees in Kahuzi-Biega National Park, Zaire. In:Great Ape Societies,McGrew,W. C.;Marchant,L. F.;Nishida,T. (eds.), Cambridge Univ. Press, Cambridge, pp. 82–98.

    Google Scholar 

  • Yamagiwa, J.;Mwanza, N. 1994. Day-journey length and daily diet of solitary male gorillas in lowland and highland habitats.Int. J. Primatol., 15: 207–224.

    Google Scholar 

  • Yamagiwa, J.;Mwanza, N.;Spangenberg, A.;Maruhashi, T.;Yumoto, T.;Fischer, A.;Steinhauer, B. B. 1993. A census of the eastern lowland gorillasGorilla gorilla graueri in Kahuzi-Biega National Park with reference to mountain gorillasG. g. beringei in the Virunga region, Zaire.Biol. Conserv., 64: 83–89.

    Article  Google Scholar 

  • Yamagiwa, J.;Mwanza, N.;Spangenberg, A.;Maruhashi, T.;Yumoto, T.;Fischer, A.;Steinhauer, B. B.;Refisch, J. 1992a. Population density and ranging pattern of chimpanzees in Kahuzi-Biega National Park, Zaire: a comparison with a sympatric population of gorillas.Afr. Stu. Monogr., 13: 217–230.

    Google Scholar 

  • Yamagiwa, J.;Mwanza, N.;Yumoto, T.;Maruhashi, T. 1992b. Travel distances and food habits of eastern lowland gorillas: a comparative analysis. In:Topics in Primatology, Vol. 2: Behavior, Ecology, and Conservation,Itoigawa,N.;Sugiyama,Y.;Sackett,G. P.;Thompson,R. K. R. (eds.), Univ. of Tokyo Press, Tokyo, pp. 267–281.

    Google Scholar 

  • Yamagiwa, J.;Mwanza, N.;Yumoto, T.;Maruhashi, T. 1994. Seasonal change in the composition of the diet of eastern lowland gorillas.Primates, 35: 1–14.

    Article  Google Scholar 

Download references

Author information

Authors and Affiliations

  1. Laboratory of Human Evolution Studies, Faculty of Science, Kyoto University, Sakyo, 606-8502, Kyoto, Japan

    Juichi Yamagiwa

Authors
  1. Juichi Yamagiwa
    View author publications

    You can also search for this author in PubMed Google Scholar

About this article

Cite this article

Yamagiwa, J. Socioecological factors influencing population structure of gorillas and chimpanzees. Primates 40, 87–104 (1999). https://doi.org/10.1007/BF02557704

Download citation

  • Received:

  • Accepted:

  • Issue Date:

  • DOI: https://doi.org/10.1007/BF02557704

Key Words

Search

Navigation