| Project/Area Number |
01041052
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| Research Category |
Grant-in-Aid for international Scientific Research
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| Allocation Type | Single-year Grants |
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| Section | Field Research |
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| Research Institution | Kyoto University |
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Principal Investigator |
NISHIDA Toshisada Kyoto University, Faculty of Science, 理学部, 教授 (40011647)
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| Co-Investigator(Kenkyū-buntansha) |
マサウエ エデウス セレンゲティ野生動物研究所, マハレセンター, 所長
HASEGAWA Mariko Senshuu University, Faculty of Law, 法学部, 助教授 (00164830)
TAKAHATA Yukio Kyoto University, Faculty of Science, 理学部, 助手 (90183061)
KURODA Suehisa Kyoto University, Faculty of Science, 理学部, 助手 (80153419)
MASSAWE Edeus Serengeti Wildlife Research Institute
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| Project Period (FY) |
1989 – 1990
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| Project Status |
Completed (Fiscal Year 1990)
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| Budget Amount *help |
¥13,300,000 (Direct Cost: ¥13,300,000)
Fiscal Year 1990: ¥3,000,000 (Direct Cost: ¥3,000,000)
Fiscal Year 1989: ¥10,300,000 (Direct Cost: ¥10,300,000)
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| Keywords | Chimpanzee / Mahale Mountains National Park / Weaning conflict / Reciprocity / Meat-sharing / Predation on chimpanzees by lions / Cannibalism / Medicinal plants |
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| Research Abstract |
At the Mahale Mountains, Tanzania, social behaviors of habituated chimpanzees were studied. Major discoveries are as follows : (1) Intense mother-offspring conflicts occurred when mothers resumed their postpartum estrus. Weaning infants were upset by mothers' weaning behaviors and protested with whimper-screams and/or violent temper tantrums when their mothers declined their requests of suckling or transport, supplanted their feeding sites, made off leaving them behind, or mated with males. Mothers reassured their infants by embracing, grooming and/or permission of incestuous mating if the infant is male. Mothers usually permitted to suckle or ride on their backs after prolonged requests by infants. Mothers frequently shared food when infants begged for it. Weaning infants interrupted mothers' mating by pushing themselves between mothers and their mates. The rate of sexual harassment by infants was the increasing function of the ages of mating partners of mothers. (2) Grooming among adult males tended to be reciprocal or mutual when they are of similar age. Young adult males tended to groom older males without being reciprocated even when the latters were lower-ranking. (3) The alpha male of the study group shared meat with particular past-prime males, but not with the second-ranking and other young higher-ranking males. He groomed with, and supported in conflicts, those males that he often gave meat. Thus, meat-sharing by the alpha male could be regarded as a coalition strategy. He also frequently shared meat with his mother and past and current mating partners. (4) Bones, hair and teeth of chimpanzees were found in the faeces of lions six times. This was the first record of predation on wild chimpanzees by non-human animals. (5) Within-group infanticide and cannibalism by adult males was observed in detail. (6) The number of intestinal parasites and the use of medicinal plants increased in the rainy season.
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