Gen Yamakoshi

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Chimpanzees (Pan troglodytes) are the most proficient and versatile users of tools in the wild. How such skills become integrated into the behavioural repertoire of wild chimpanzee communities is investigated here by drawing together evidence from three complementary approaches in a group of oil-palm nut- (Elaeis guineensis) cracking chimpanzees at Bossou,(More)
  • G Yamakoshi
  • American journal of physical anthropology
  • 1998
A 13-month ecological study was conducted at Bossou, Guinea, West Africa, to elucidate how a community of wild chimpanzees (Pan troglodytes verus) deals with the scarcity of main foods. During the study period, fruit availability fluctuated radically. The chimpanzees were confirmed to depend heavily on three "keystone resources" which were available when(More)
Ant-dipping behavior is often cited as a clear example of chimpanzee culture, since different populations have apparently different dipping techniques (the one-handed method used by chimpanzees in Bossou, Guinea and Taï, Côte d’Ivoire, and the two-handed method used in Gombe, Tanzania). Here we report a new observation of ant-dipping behavior from Bossou(More)
Wild chimpanzees are known to have a different repertoire of tool use unique to each community. For example, "ant-dipping" is a tool use behavior known in several chimpanzee communities across Africa targeted at driver ants (Dorylus spp.) on the ground, whereas "ant-fishing," which is aimed at carpenter ants (Camponotus spp.) in trees, has primarily been(More)
Chimpanzees (Pan troglodytes verus) were observed capturing and toying with western tree hyraxes (Dendrohyrax dorsalis, Order Hyracoidea) at Bossou, Guinea. An adolescent female carried one hyrax for 15 hr, slept with it in her nest, and groomed it. The captive was not consumed. Nearby adults ignored the hyrax. In another case, two adolescent males timidly(More)
With the conversion of natural habitats to farmland, nonhuman primates (hereafter primates) are increasingly exposed to agricultural crops. Although frugivorous primates are important seed dispersers that sometimes feed on agricultural fruits, evidence for dispersal of crops by primates is lacking. Here, we examine flexible feeding on cacao (Theobroma(More)
A new type of tool-using behavior was observed in a group of wild chimpanzees (Pan troglodytes verus) at Bossou, Guinea. The chimpanzees used the leaf-petiole of oil-palm trees (Elaeis guineensis) as a pounding tool to deepen a hole in the oil-palm crown which appeared after the chimpanzees had pulled out the central young shoots. Finally, the chimpanzees(More)
Attacks on humans by nonhuman primates are one of the most serious causes of human-primate conflict, and strongly influence people's perceptions and tolerance of nonhuman primates. Despite their importance, systematic and extensive records of such attacks are rare. Here, we report the attacks that occurred on local persons by chimpanzees (Pan troglodytes(More)
African apes and humans share a genetic mutation that enables them to effectively metabolize ethanol. However, voluntary ethanol consumption in this evolutionary radiation is documented only in modern humans. Here, we report evidence of the long-term and recurrent ingestion of ethanol from the raffia palm (Raphia hookeri, Arecaceae) by wild chimpanzees (Pan(More)
______________________________________ As an increasing number of field studies of chimpanzees (Pan troglodytes) have achieved long-term status across Africa, differences in the behavioural repertoires described have become apparent that suggest there is significant cultural variation 1-7. Here we present a systematic synthesis of this information from the(More)
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