Characteristics of the wild Japanese macaque population reached to the carrying capacity and mechanisms of population control.

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The population of wild animals could be controlled by the carrying capacity that natural condition allow them to take enough foods and other needs. It is likely that wild population of Japanese macaques did not reach the maximum density in many districts in the former days. Recently, population increase have been reported from many areas and some population can be regarded as to reach the maximum density allowed in their surrounding environment. The population in the Koshima Island, Shimokita Peninsula, and some other areas where belong to the Field Research Center, Primate Research Institute, Kyoto University was examined. The aim of the study is to make clear the characteristics and mechanisms of population control in the relevant environments. The Koshima group have already kept a stable population for these 30 years. Birth ratio decreased and infant mortality increased. Most kin groups have maintained their descendants through these 50 years. However, some subordinate family groups disappeared or rapidly decreasing in number within these ten years. The reason that most population continued until now could be the reflection that large number of females were prepared during the periods when population in the group increased. In the Shimokita peninsula, population increased during these 30 years up to three times from about 200 in 1970 to 750 in 1999. The area shimokita groups distributed became wider and wider as the time passed by. However, southern groups still keep smaller home ranges, 2-3 kmィイD12ィエD1, while northern groups possess wider ranges up to 80 kmィイD12ィエD1. Wild monkey groups are also studied in Yakushima, Johshinetsu and Kiso.