Mating patterns and reproductive strategies in a community of wild chimpanzees (Pan troglodytes schweinfurthii)
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The sexual behaviour of a chimpanzee community in the Gombe National Park, Tanzania, was studied intensively for 16 months. Additional information came from 15 years of demographic and behavioural data accumulated by Jane Goodall and members of the Gombe Stream Research Centre.
The mating system of the Gombe chimpanzees is flexible and comprises three distinct mating patterns: (a) opportunistic, non-competitive mating, when an oestrous female may be mated by all the community males; (b) possessiveness, when a male forms a special short-term relationship with an oestrous female and may prevent lower-ranking males from copulating with her; and (c) consortships, when a male and a female leave the group and remain alone, actively avoiding other chimpanzees. While males took the initiative in possessive behaviour and consortships, females had to cooperate for a successful relationship to develop.
Data from 14 conceptions indicated that the majority of females (9) became pregnant while participating in the restrictive mating patterns, possessiveness and consorting. It could be established definitely that seven of these females were consorting during the cycle in which they conceived. As 73% of the 1137 observed copulations occurred during opportunistic mating, 25% during possessiveness, and only 2% during consortships, there was no correlation between copulation frequency and reproductive success.
Adult males showed differential frequencies of participation in the restrictive mating patterns. Male age, dominance rank, and the amount of agonistic behaviour directed to females showed no correlation with participation in the restrictive mating patterns. The following male characteristics did show significant, positive correlations with involvement in the restrictive mating patterns: (a) the amount of time spent in the same group as oestrous females, (b) the proportion of that time spent grooming oestrous females in groups, and (c) the frequency with which males shared food with females. While dominance ranks of the adult males showed no consistent correlation with involvement in the restrictive mating patterns, it was clear that the most dominant male did gain an advantage. He was the only male able to monopolise oestrous females by showing possessive behaviour.
Consortships appeared to be the optimal reproductive strategy for males (with the exception of the most dominant) and females, as they gave males the highest probability of reproductive success, and allowed females to exercise choice. However, there appeared to be disadvantages associated with consort formation; the greatest of these was the increased risk of intercommunity encounters. While all individuals have the potential to practice each mating pattern, the strategy actually used at any moment will be determined by variables both within the individual, e.g. age, physical condition, dominance position; and by social factors in the group, e.g. general stability of male dominance relationships, presence of a strong alpha male, existence of special male-female relationships.
KeywordsReproductive Strategy Dominance Rank Mating Pattern Wild Chimpanzee Alpha Male
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- Altmann, J.: Observational study of behaviour: Sampling methods. Behaviour 49, 227–266 (1974)Google Scholar
- Bygott, D.: Cannibalism among wild chimpanzees. Nature 238, 410–411 (1972)Google Scholar
- Bygott, D.: Agonistic behaviour, dominance and social structure in the wild chimpanzees of Gombe National Park. In: The great apes. Perspectives on human evolution, Vol. 5. Hamburg, D.A., McCown, E.R. (eds.). Menlo Park, California: Benjamin/Cummings 1979Google Scholar
- Goodall, J.: Chimpanzees of the Gombe Stream Reserve. In: Primate behaviour. DeVore, I. (ed.), pp. 425–473. New York: Holt, Rinehart & Winston 1965Google Scholar
- Goodall, J., Bandura, A., Bergmann, E., Busse, C., Matama, H., Mpongo, E., Pierce, A., Riss, D.: Inter-community interactions in the chimpanzee population of the Gombe National Park. In: The great apes. Perspectives on human evolution, Vol. 5. Hamburg, D.A., McCown, E.R. (eds.) Menlo Park, California: Benjamin/Cummings 1979Google Scholar
- Graham, C.E.: Reproductive physiology of the chimpanzee. The chimpanzee, Vol. 3, pp. 183–220. Basel: Karger 1970Google Scholar
- Graham, C.E.: Chimpanzee endometrium and sexual swelling during menstrual cycle or hormone administration. Folia Primatol. 19, 458–568 (1973)Google Scholar
- Graham, C.E.: Menstrual cycle physiology of the great apes. In: Reproductive biology of the great apes. Graham, C.E. (ed.) New York: Academic 1979 (in press)Google Scholar
- Kortlandt, A.: Chimpanzees in the wild. Sci. Am. 206, 128–138 (1962)Google Scholar
- Lawick-Goodall, J. van: The behaviour of the chimpanzee. In: Hominisation und Verhalten. Eibl-Eibesfeldt, I. (ed.), pp. 56–100. Stuttgart: Gustav Fischer 1975Google Scholar
- Lawick-Goodall, J. van: The behaviour of free-living chimpanzees in the Gombe Stream Reserve. Anim. Behav. Monogr. 1, 161–311 (1968)Google Scholar
- McGinnis, P.R.: Patterns of sexual behaviour in a community of free living chimpanzees. Ph.D. thesis, University of Cambridge (1973)Google Scholar
- McGinnis, P.R.: Sexual behaviour in free-living chimpanzees: Consort relationships. In: The great apes. Perspectives on human evolution, Vol. 5. Hamburg, D.A., McCown, E.R. (eds.) Menlo Park, California: Benjamin/Cummings 1979Google Scholar
- McGrew, W.C.: Patterns of plant food sharing by wild chimpanzees. In: Contemporary primatology. Kondo, S., Kawai, M., Ehara, A. (eds.) pp. 304–309. Basel: Karger 1975Google Scholar
- Nishida, T.: The social group of wild chimpanzees in the Mahali Mountains. Primates 9, 167–224 (1968)Google Scholar
- Nishida, T.: The social structure of chimpanzees of the Mahali Mountains. In: The great apes. Perspectives on human evolution, Vol. 5. Hamburg, D.A., McCown, E.R. (eds.). Menlo Park, California: Benjamin/Cummings 1979Google Scholar
- Nissen, H.W., Yerkes, R.M.: Reproduction in the chimpanzee: Report on forty-nine births. Anat. Rec. 86, 567–578 (1943)Google Scholar
- Pusey, A.: Inter-community transfer of chimpanzees in Gombe National Park. In: The great apes. Perspectives on human evolution, Vol. 5. Hamburg, D.A., McCown, E.R. (eds.). Menlo Park, California: Benjamin/Cummings 1979Google Scholar
- Riss, D.C., Goodall, J.: The recent rise to the alpha-rank position in a population of free-living chimpanzees. Folia Primatol. 27, 134–151 (1977)Google Scholar
- Rowell, T.E.: Female reproduction cycles and social behaviour in primates. Adv. Study Behav. 4, 69–105 (1972)Google Scholar
- Simpson, M.J.A.: The social grooming of male chimpanzees. In: Comparative ecology and behaviour of primates. Michael, R.P., Crook, J.H. (ed.), pp. 411–506. London: Academic 1973Google Scholar
- Suzuki, A.: Carnivority and cannibalism observed among forest-living chimpanzees. J. Anthropol. Soc. Nippon (Zinruigaku Zasshi) 79, 30–48 (1971)Google Scholar
- Tutin, C.E.G.: Exceptions to promiscuity in a feral chimpanzee community. In: Contemporary primatology. Kondo, S., Kawai, M., Ehara, A., (eds.), pp. 445–449. Basel: Karger 1975Google Scholar
- Tutin, C.E.G.: Responses of chimpanzees to copulation, with special reference to interference by immature individuals. Anim. Behav. 27 (in press) (1979)Google Scholar
- Tutin, C.E.G., McGinnis, P.R.: Reproduction of the chimpanzee in the wild. In: Reproductive biology of the great apes. Graham, C.E., (ed.) New York: Academic (1979) (in press)Google Scholar
- Tutin, C.E.G., McGrew, W.C.: Sexual behaviour of group-living adolescent chimpanzees. Am. J. Phys. Anthropol. 38, 195–199 (1973)Google Scholar
- Wrangham, R.W.: Behavioural ecology of chimpanzees in Gombe National Park, Tanzania. Ph.D. thesis, University of Cambridge (1975)Google Scholar
- Wrangham, R.W.: Feeding behaviour of chimpanzees in Gombe National Park, Tanzania. In: Primate ecology. Clutton-Brock, T.H., (ed.) pp. 504–538. London: Academic 1977Google Scholar