1987 Fiscal Year Final Research Report Summary
Adaptive Strategies and Evoluteonary Trend of Pygmy Chimpanzees(Pan paniscus)
| Project/Area Number |
62043067
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| Research Category |
Grant-in-Aid for Overseas Scientific Survey.
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| Allocation Type | Single-year Grants |
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| Section | 調査総括 |
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| Research Institution | Kyoto University |
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Principal Investigator |
KANO Takayoshi Professor,Dept.of Sociology,Kyoto University Primate Research Institute, 霊長類研究所, 教授 (40045050)
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| Co-Investigator(Kenkyū-buntansha) |
黒田 未寿 京都大学, 理学部, 助手 (80153419)
ASATO Ryu Lecturer,Faculty of Medicine,University of the Ryukyus, 医学部, 講師 (60045052)
KAWANAKA Kenji Professor,Faculty of Sciende,Okayama-Rika University, 理学部, 教授 (70020790)
KURODA Suehisa Assistant,Faculty of Sclence,Kyoto University
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| Project Period (FY) |
1987
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| Keywords | Pygmy chimpanzee / Common chimpanzee / Pan paniscus / Pan troglodytes Social organization / Sexual behavior / Social behavior / Demography / community / Intergroup relationships / Pan paniscus / Pan troglodytes |
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| Research Abstract |
1.In pygmy chimpanzee societies,a variety of appeasement behaviors well developed to smooth the coexistence of group members.The appeasement behaviors such as GG-rubbing, mounting and urmp contact originated from copulatory behavior.Heterosexual copulation itself appear to be used more frequently for lowering tension between males and females rather than for the purpose of reproduction.
2.Absence of intraspecific killings(i.e.,infanticide and intergroup killing)results in the male-female equality in group cpmposition,which is one of the social characteristics of pygmy chimpanzees.Roles of males are not fixed in pygmy chimpanzee groups. Alpha male in one group formed a center of male attention structure,while young alpha male in another group was successful in dominating others by the assistance of his mother.
3.Young mulliparous females adopted a special strategy to immigrate into a new group. At first they found out elder parous females who were not aggressive to them,and then followed
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and positively seeked intimate contacts with them.Those "target"parous females seemed to play an important role in the group transfer of young nulliparous females by supporting and assisting them in obtaining the approval of the other group members.
4.During the present study period,the intergroup relationships between the EL and P groups whech used to be antagonistic were much improved.Twenty two intergroup encounters between EL and P were observed for about 16 hours at the artificial feeding places. All kinds of friendly interactions as well as aggressive ones were observed there. Such interactions included GG-rubbings,rump contact,heterosexual copulations,starings, food-beggings and social plays.The repertoire of the intergroup interaction patterns were quite identical to that of the intragroup ones.Such intimacy between groups is not recorded in other nonhuman primates.The intergroup interaction patterns show that the community structure of pygmy chimpanzees is varied from severe antagonism to mutual tolerancy or true friendship.The community of human type may have evolved from such flesible community structure as pygmy chimpanzees'. Less
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Research Products
(19 results)
