Abstract
A small population of wild chimpanzees was studied at Bossou, Guinea, for six months from November 1976 to May 1977. All the chimpanzees except dependent infants were identified without artificial feeding and were observed from within 20 m almost every day. The population size of 21 chimpanzees was little changed from 1967. Although the sex ratio (male/female) of immatures (infants, juveniles, and adolescents) was 0.833 in January 1977, the adult sex ratio was 0.429. More than half of the males must therefore have disappeared. No desertion of males from the Bossou group was confirmed during the study period but two emigrated males from other groups did come to join the Bossou group for a short period.
Four out of six mothers had two or three children. From the age discrepancy of brothers/sisters, the mean birth interval from a mother was estimated to be about four years. An elder sister of two infants who had an age-gap of only three years, or perhaps less, disappeared without receiving sufficient care from her mother.
Mothers who had infants aged about 1 year or more showed swelling of their sexual skin and were confirmed to mate with males.
Similar content being viewed by others
References
Albrecht, H. &S. C. Dunnet, 1971.Chimpanzees in Western Africa. Piper, München.
Goodall, J., 1965. Chimpanzees of the Gombe Stream Reserve. In:Primate Behavior,I. DeVore (ed.), Holt Rinehart, & Winston, N. Y., pp. 425–473.
Hanby, J., 1976. Sociosexual development in primates. In:Perspectives in Ethology, Vol. 2,P. G. Bateson &P. H. Klopfer (eds.), Plenum Press, N. Y., pp. 1–67.
Itani, J., 1972.Social Structure of Primates. Kyoritsu-Shuppan, Tokyo. (in Japanese)
Kawanaka, K. &T. Nishida, 1975. Recent advances in the study of inter-unit-group relationships and social structure of wild chimpanzees of the Mahali Mountains. In:Proc. Symp. Vth Congr. Intern. Primat. Soc.,S. Kondo,M. Kawai,S. Kawamura, &A. Ehara (eds.), Japan Science Press, Tokyo, pp. 173–186.
Kortlandt, A., 1962. Chimpanzees in the wild.Sci. Amer., 206(5): 128–138.
Lawick-Goodall, J. van, 1968. The behaviour of free-living chimpanzees in the Gombe Stream Reserve.Anim. Behav. Monogr., 1(3): 161–311.
Napier, J. R. &P. H. Napier, 1967.A Handbook of Living Primates. Academic Press, London.
Nishida, T., 1968. The social group of wild chimpanzees in the Mahali Mountains.Primates, 9: 167–224.
————, 1977. Social structure of chimpanzees. In:Anthropology Series, Vol. 2, Primates,J. Itani (ed.), Yuzankaku, Tokyo, pp. 277–314. (in Japanese)
————, 1972. Inter-unit-group relationships among wild chimpanzees of the Mahali Mountains.Kyoto Univ. African Stud., 7: 131–169.
Reynolds, V., 1966. Open groups in hominid evolution.Man (N. S.) 1(4): 441–452.
————, 1965. Chimpanzees of the Budongo Forest. In:Primate Behavior,I. DeVore (ed.), Holt, Rinehart, & Winston, N. Y., pp. 368–424.
Sugiyama, Y., 1968. Social organization of chimpanzees in the Budongo Forest, Uganda.Primates, 9: 225–258.
————, 1973. The social structure of wild chimpanzees—A review of field studies. In:Comparative Ecology and Behaviour of Primates,R. P. Michael &J. H. Crook (eds.), Academic Press, London, pp. 375–410.
————, 1976. Life history of male Japanese monkeys. In:Advances in the Study of Behaviour, Vol. 7,J. S. Rosenblatt &R. Hinde (eds.), Academic Press, London, pp. 255–284.
————, 1978.Peoples and Chimpanzees of Bossou. Kinokuniya Shoten, Tokyo. (in Japanese)
----, (in press)Life Science Series, Vol. 15: Behaviour. Kyoritsu-Shuppan, Tokyo. (in Japanese)
Suzuki, A., 1971. Carnivority and cannibalism observed among forest living chimpanzees.J. Anthrop. Soc. Nippon, 79: 30–48.
Author information
Authors and Affiliations
About this article
Cite this article
Sugiyama, Y., Koman, J. Social structure and dynamics of wild chimpanzees at Bossou, Guinea. Primates 20, 323–339 (1979). https://doi.org/10.1007/BF02373387
Received:
Accepted:
Issue Date:
DOI: https://doi.org/10.1007/BF02373387