Chimpanzees using stones to crack open oil palm nuts in Liberia
@article{Hannah2006ChimpanzeesUS, title={Chimpanzees using stones to crack open oil palm nuts in Liberia}, author={Alison C. Hannah and William C. McGrew}, journal={Primates}, year={2006}, volume={28}, pages={31-46} }
The use of stone-tools to open palm nuts (Elaeis guineensis) was studied in a group of 16 chimpanzees (Pan troglodytes) released from captivity to a natural island setting in Liberia. The behaviour was started by one female of the group; it then spread to 12 others over periods varying from a few seconds to a few weeks. Nut-cracking soon spread to three other sites, both spontaneously and with human encouragement. Both nuts and tools were carried distances of several hundred meters. Social…
59 Citations
Why Don't Chimpanzees in Gabon Crack Nuts?
- BiologyInternational Journal of Primatology
- 2004
The behavioral differences across populations of these apes are cultural and not environmentally dictated, leaving by exclusion the likelihood that Lopé's chimpanzees lack the technology—knowledge of appropriate technique—to exploit this resource.
How does stone-tool use emerge? Introduction of stones and nuts to naïve chimpanzees in captivity
- Biology, PsychologyPrimates
- 2004
The cognitive capability required for nut-cracking behavior and the process through which the nut-Cracking behavior emerges are clarified and the patterns of object manipulation exhibited by the subjects are analyzed.
Flexibility of wild chimpanzee nut-cracking behavior using stone hammers and anvils : an experimental analysis
- Biology
- 2010
Analysis of experiments such as separating nuts and stones found under palm trees revealed the chimbanzees' flexibility in tool use, which appears to stem from the chimpanzees' understanding of the relationship between tools and referents, i.e. the function of tools.
Social learning of nut-cracking behavior in East African sanctuary-living chimpanzees (Pan troglodytes schweinfurthii).
- Biology, PsychologyJournal of comparative psychology
- 2008
Results confirmed that nut cracking can be acquired in a matter of days by social learning, but only in chimpanzees 3 to 4 years old and older, and with striking similarities in developmental profiles.
How to crack nuts: acquisition process in captive chimpanzees (Pan troglodytes) observing a model
- PsychologyAnimal Cognition
- 2009
Stone tool use for nut cracking consists of placing a hard-shelled nut onto a stone anvil and then cracking the shell open by pounding it with a stone hammer to get to the kernel. We investigated the…
Optional tool use: The case of wild bearded capuchins (Sapajus libidinosus) cracking cashew nuts by biting or by using percussors
- BiologyAmerican journal of primatology
- 2020
It is suggested that success at opening cashews with a tool 1–2 years earlier than they succeed at cracking more resistant palm nuts may support the monkeys' persistent efforts to crack palm nuts.
Distribution of potential suitable hammers and transport of hammer tools and nuts by wild capuchin monkeys
- BiologyPrimates
- 2008
Findings show that wild capuchin monkeys selectively transport stones of appropriate size and hardness to use as hammers, thus exhibiting, like chimpanzees and humans, planning in tool-use activities.
Complex tool sets for honey extraction among chimpanzees in Loango National Park, Gabon.
- BiologyJournal of human evolution
- 2009
Nut Cracking Tools Used by Captive Chimpanzees (Pan troglodytes) and Their Comparison with Early Stone Age Percussive Artefacts from Olduvai Gorge
- BiologyPloS one
- 2016
This study represents the first direct comparison of chimpanzee pounding tools and archaeological material, and thus may contribute to a better understanding of hominin percussive activities.
Chaînes opératoires and resource-exploitation strategies in chimpanzee (Pan troglodytes) nut cracking.
- BiologyJournal of human evolution
- 2008
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