Study on African Primates in the Forest and the Openland

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Field researches both in a topical forest and an open land in Africa was conducted to clarify the feature of adaptation and process of dispersion of cercopiethecid monkeys in forests and into open lands.Research in a forest was conducted at the Nature Reserve of Ipassa-Mingouri in Gabon this year following the previous year. Hamada accompanied a research collaborator Okayasu (Howletts Institute, United Kingdom). In the vocal communication studies of colobus monkeys and cercopiethecid monkeys they collected vocal response of monkeys to vocal sounds of individuals in their own group and those in the neighbouring groups. Then they analyzed the vocal repertory and the function of the collected data of vocal sound. They also collected the data on foraging behaviours and food items of monkeys following the previous year. (conducted mainly by Okayasu). Hamada collected the morphological data on locomotion mastication and vocalization of colobus and cercopiethecid monkeys.Research in a savanna was conducted at Kala Maloue National Park in Cameroon by Ohsawa, Agetsuma, Njifoti (Foreign investigator of this research project) and Chatani (research collaborator: JSPS post-doctoral researcher). Following surveys were conducted. 1. Data on foraging activity dairy rhythm and food items of patas monkeys in the rain season were collected (Agetsuma). 2. Data on terrestrial locomotion patterns of patas monkeys were collected through observation and in videotapes. Date on whole day long of 2 individuals of each year from 0.5 to 4.5 were collected (Chatani). 3. The process of supplanting of the harem male of one-male group by a solitary male was investigated through direct observation. In this year submissive males were observed to copulated more frequently than the males in average.