, Volume 9, Issue 3, pp 167–224 | Cite as

The social group of wild chimpanzees in the Mahali Mountains

  • Toshisada Nishida


There are more than six large groups of wild chimpanzees in the study area, which is in the north-eastern part of the Mahali Mountains of Western Tanzainia. One of these groups was provisionized, that is, customarily fed sugar cane and bananas. The characteristics of the social group of wild chimpanzees are clarified by long-term observation of the baited population. The chimpanzees live in a clear-cut social unit which consists of adult males, adult females, and immature animals. The permanency, stable membership, and integrative nature of the unit-group were confirmed during the course of this study. The size of unit-groups ranges from 30 to 80 head.

The unit-group generally splits up into temporary subgroups that repeat joining and parting. The size of the subgroups of the baited population ranges from one to 28 head, the mean being 8.1 head. The centralization of a unitgroup is mainly sustained by the high sociability of adult males. The random nature of the membership of subgroups is emphasized in this paper, although subgroups are usually composed by social bonds on the basis of similar age, sex, blood relationship, and/or sexual attraction.

The inter-unit-group interaction is peaceful; the subordinate unit-group avoids the dominant one. The home ranges of unit-groups overlap each other extensively, the overlapping areas being used flexibly by both unit-groups on the basis of dominance-subordination relationship. The member-exchange among unit-groups may sometimes occur, but the extent of openness or closedness of a unit-group has not been well elucidated.


Cane Home Range Adult Male Social Group Social Bond 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.


Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.


  1. Aldrich-Blake, F. P., 1966. Some aspects of blue monkey social organization. Presented at the 4th East African Academy Symposium, Kampala, on September 21, 1966.Google Scholar
  2. Azuma, S. &A. Toyoshima, 1961–62. Progress report of the survey of chimpanzees in their natural habitat, Kabogo Point Area, Tanganyika.Primates, 3(2): 61–70.Google Scholar
  3. -- & --, 1965. Chimpanzees in Kabogo Point Area, Tanganyika. In:Monkeys and Apes,S. Kawamura & J. Itani (eds.) pp. 127–183.Google Scholar
  4. Chance, M. R. A., 1967. Open groups in hominid evolution.Man (N. S.), 2(1): 130–131.Google Scholar
  5. Goodall, J., 1963. My life among wild chimpanzees.National Geographic Magazine 124(2): 272–308.Google Scholar
  6. ——, 1965. Chimpanzees of Gombe Stream Reserve. In:Primate Behavior: Field Studies of Monkeys and Apes,I. DeVore (ed.) Holt, Rinehart & Winston, New York.Google Scholar
  7. ——, 1966. New discoveries among Africa's chimpanzees.National Geographic Magazine, 128(6): 802–831.Google Scholar
  8. --, 1967.My Friends: The Wild Chimpanzees. National Geographic Society.Google Scholar
  9. Imanishi, K., 1961. The origin of human family: A primatological approach.Jap. J. Ethnol. 25: 119–130.Google Scholar
  10. Itani, J., 1954. Japanese monkeys at Takasakiyama. In:Nihon Dobutsu-ki, II,K. Imanishi (ed.) Kobunsha, Tokyo.Google Scholar
  11. Itani, J., 1966. The social organization of chimpanzees.Shizen, 21(8): 17–30.Google Scholar
  12. ——, 1967. From the societies of non-human primates to human society.Kagaku, 37(4): 170–174.Google Scholar
  13. ——, 1967. The social unit of chimpanzees.Primates, 8(4): 355–381.Google Scholar
  14. Izawa, K. &J. Itani, 1966. Chimpanzees in Kasakati Basin, Tanganyika. (I) Ecological study in the rainy season 1963–1964.Kyoto University African Studies, 1: 73–156.Google Scholar
  15. Kortlandt, A., 1962. Chimpanzees in the wild.Sci. Amer., 206(5): 128–138.Google Scholar
  16. ——, 1963. Protohominid behavior in primates (Preliminary Communication).Symp. Zool. Soc. London. No. 10. pp. 61–87.Google Scholar
  17. Langdale-Brown, I., H. A. Osmaston, & J. G. Wilson, 1964.The Vegetation of Uganda and Its Bearing on Land-use. Published by the Government of Uganda.Google Scholar
  18. Nishida, T., 1966. A sociological study of solitary male monkeys.Primates, 7(2): 141–204.Google Scholar
  19. ——, 1967. The society of wild chimpanzees.Shizen, 22(8): 31–41.Google Scholar
  20. Reynolds, V. &F. Reynolds, 1965. Chimpanzees of the Budongo Forest. In:Primate Behavior: Field Studies of Monkeys and Apes,I. DeVore, (ed.) Holt, Rinehart & Winston, New York.Google Scholar
  21. ——, 1966. Open groups in hominid evolution.Man (N. S.), 1: 441–452.Google Scholar
  22. Schaller, G.B., 1963.The Mountain Gorilla: Ecology and Behavior. The University of Chicago Press, Chicago and London.Google Scholar
  23. ——, 1965. Behavioral comparison of the apes. In:Primate Behavior: Field Studies of Monkeys and Apes,I. DeVore, (ed.) Holt, Rinehart & Winston, New York.Google Scholar
  24. Simkin, P. &B. Juniper, 1961. Report of the University of Oxford Expedition to Tanganyika, 1958.Oxford University Exploration Club Bulletin, No. 10 pp. 2–12.Google Scholar
  25. Stevens, T. E., 1962. Oxford University Tanganyika Expeditions 1958–9.Tanganyika Notes and Records, Nos. 58 & 59 pp. 111–115.Google Scholar
  26. Sugiyama, Y., 1968. Social organization of chimpanzees in the Budongo Forest, Uganda.Primates, 9(3): 225–258.Google Scholar
  27. Suzuki, A., (in press) An ecological study of chimpanzees living in a savanna woodland.Primates, 10(2):Google Scholar

Copyright information

© Japan Monkey Centre 1968

Authors and Affiliations

  • Toshisada Nishida
    • 1
  1. 1.Laboratory of Physical AnthropologyKyoto UniversityKyotoJapan

Personalised recommendations