2013 Fiscal Year Final Research Report
Behavioral study on aged females in free-ranging groups of Japanese macaques
| Project/Area Number |
23653225
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| Research Category |
Grant-in-Aid for Challenging Exploratory Research
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| Allocation Type | Multi-year Fund |
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| Research Field |
Experimental psychology
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| Research Institution | Osaka University |
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Principal Investigator |
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| Project Period (FY) |
2011 – 2013
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| Keywords | ニホンザル / 老化 / 毛づくろい / 高齢 / 社会的孤立 |
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| Research Abstract |
We observed females of various age classes in free-ranging groups of Japanese macaques. We found that some aged females aged around 25 years or more got dim with age; aged eyes or farsightedness due to old age through observations of their grooming behaviors. The distance between eyes and fingers during grooming others for some aged females was much longer than that for younger females, indicating that the former females have aged eye. This is the first finding of aged eye in monkey species.
There is a clear tendency that aged and lower-ranking females became less social than aged but higher-ranking females. Such social withdrawal or decreasing social attractiveness seem to be related with dominance rank and the number of female immmature offspring.
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