著者

武田 庄平 筒井 紀久子 松沢 哲郎

出版者

日本霊長類学会

雑誌

霊長類研究 (ISSN:09124047)

巻号頁・発行日

vol.15, no.2, pp.207-214, 1999 (Released:2009-09-07)

参考文献数

13

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Sand manipulations in four captive female chimpanzees (Pan troglodytes) were experimentally analysed. Every experimental session was done at the individual situation. Each individual was observed in the experimental booth under four 30min. conditions; with an experimenter and no object, with an experimenter and 16 objects, with an experimenter and 7 objects, and with no experimenter and 7 objects. In every conditions, 10kg. sand was mounted at the centre of floor in the booth. Comparing the amount of time of sand manipulations under each conditions, the conditions with an experimenter and objects facilitated chimpanzees to manipulate sand, although the small number of objects was more efficient. For the ultimate purpose of abstracting the intelligence of chimpanzee, we made the ethogram of sand manipulation. Each bout of sand manipulation observed was categorized into four contexts; relating with their own body and object, relating with only their own body, relating with only object, and specific manipulation. The cases of sand manipulation initiated with “scoop”, “drop”, “grasp”, “scrape”, and “touch” were the most popular for all contexts. Chimpanzees could spontaneously construct the triad relationship of sand (with objects), experimenter, and themselves. Apparent “pretend play” could not be observed in the present study, but some of nearly “pretend play” were observed. These observational evidences allowed us to speculate that chimpanzees can symbolically manipulate sand.