1992 Fiscal Year Final Research Report Summary
Observational and experimental studies on the influence of social status on feeding strategies
| Project/Area Number |
02640509
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| Research Category |
Grant-in-Aid for General Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Research Field |
生態学
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| Research Institution | KYOTO UNIVERSITY |
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Principal Investigator |
SUGIYAMA Yukimaru Kyoto University Primate Research Institute,Professor, 霊長類研究所, 教授 (20025349)
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| Co-Investigator(Kenkyū-buntansha) |
YAMAGIWA Juichi Kyoto University Primate Research Institute,Instructor, 霊長類研究所, 助手 (60166600)
MORI Akio Kyoto University Primate Research Institute,Associate Professor, 霊長類研究所, 助教授 (50027504)
OHSAWA Hideyuki Kyoto University Primate Research Institute,Associate Professor, 霊長類研究所, 助教授 (60027498)
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| Project Period (FY) |
1990 – 1992
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| Keywords | Japanese monkeys / social status / feeding strategies / amount of food intake / feeding speed / food patch / birth rate / models of local population |
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| Research Abstract |
Experiment was conducted on the Japanese monkey group of the Koshima group in order to know the difference of intake process of artificial food among different age,rank classes.Soy beans were given widely scattered on the ground,and individual monkeys were counted to pick up beans. Young individuals (less than 5 years)showed advantageous intake of given beans than elders when a amount of beans were dived and given in several times than the same amount being given at one time. This result indicates that younger individuals feeding is adaptive to many scattered small food patches,than limited numbers of big patches. The high ranking females showed high intake of given beans,while females of other rank classes did not show rank dependent advantageous feeding. Different class adopted different strategies of feeding. And second higher rank class females showed less adaptive strategies than the low rank class females. This corresponded low reproductive success of second high rank class females in the Koshima group. Population changes of monkeys of Takasakiyama were studied since 1971 as a model of artificially fed groups. We analyzed the accumulated data. The Takasakiyama groups depended2/3(-1/2)of their food intake of the artificially given food. The amount of given food strongly showed the direct relationship with the birth rates of the groups. Birth rates significantly differed between rank classes of females. Lower class females made much effort to prolong their feeding duration, while their intake did not reach the feeding amount of high rank female class despite their efforts. Depending these studies, models of population and social dynamics of different groups living in wide varieties of environment,from broad leaf ever green Yakushima habitat to the snowy northern,tohoku, districts.
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