An ecological study of chimpanzees in a savanna woodland

From May, 1964, to September, 1965, the author made ecological and sociological studies of wild chimpanzees (Pan troglodytes) in Western Tanzania, East Africa, and found that the continuity of the group of chimpanzees is not stable but temporary, as has been reported by Goodall, etc.

Abstract

From May, 1964, to September, 1965, the author made ecological and sociological studies of wild chimpanzees (Pan troglodytes) in Western Tanzania, East Africa. The vegetation of this area belongs to theBrachystegia andIsoberlinia savanna woodland. During the dry season, chimpanzees go out into the open forest and chiefly eat the hard seeds ofJulbernardia, Brachystegia, Isoberlinia, Pterocarpus, etc. The continuity of the group of chimpanzees is not stable but temporary, as has been reported byGoodall, etc. The author termed such a temporary group "nomadic group." A big nomadic group, such as that consisting of 43 individuals at Filabanga, seems to be one unit of a chimpanzee's society. The nomadic range of the chimpanzees in the savanna woodland covers about 100 km2 (201 km2 in the Kasakati area). This is greater than that of the chimpanzees living in the forest, and such a large range has not been previously known among other non-human primates.