Chimpanzees use stone hammers in Cameroon

Morgan, Bethan J.; Abwe, Ekwoge E.

doi:10.1016/j.cub.2006.07.045

Cited by 79 publications

(57 citation statements)

References 7 publications

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“…Setting aside regional variations in behaviour that were likely explicable by environmental differences, this analysis identified 39 putative traditions. One of the clearest is the percussive activity of nut-cracking, which occurs across a swathe of far-west Africa about 700 km from north to south [13], but not in central or East Africa (an earlier report based on cracked nuts in Cameroon [26] remains unconfirmed). This behaviour appears robust with respect to the potential difficulty of reliably excluding environmental explanations for the differences documented: two independent expeditions to non-nut-cracking locations confirmed that the raw materials of nuts and suitable hammers were readily available [27,28].…”

Section: Experimental Studies Of Nut-cracking By Chimpanzees (A) Backmentioning

confidence: 99%

Experimental studies illuminate the cultural transmission of percussive technologies inHomoandPan

Whiten¹

2015

Phil. Trans. R. Soc. B

100

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The complexity of Stone Age tool-making is assumed to have relied upon cultural transmission, but direct evidence is lacking. This paper reviews evidence bearing on this question provided through five related empirical perspectives. Controlled experimental studies offer special power in identifying and dissecting social learning into its diverse component forms, such as imitation and emulation. The first approach focuses on experimental studies that have discriminated social learning processes in nut-cracking by chimpanzees. Second come experiments that have identified and dissected the processes of cultural transmission involved in a variety of other force-based forms of chimpanzee tool use. A third perspective is provided by field studies that have revealed a range of forms of forceful, targeted tool use by chimpanzees, that set percussion in its broader cognitive context. Fourth are experimental studies of the development of flint knapping to make functional sharp flakes by bonobos, implicating and defining the social learning and innovation involved. Finally, new and substantial experiments compare what different social learning processes, from observational learning to teaching, afford good quality human flake and biface manufacture. Together these complementary approaches begin to delineate the social learning processes necessary to percussive technologies within the Pan – Homo clade.

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Section: Experimental Studies Of Nut-cracking By Chimpanzees (A) Backmentioning

confidence: 99%

Experimental studies illuminate the cultural transmission of percussive technologies inHomoandPan

Whiten¹

2015

Phil. Trans. R. Soc. B

100

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“…Several lines of evidence now indicate that chimpanzees designated as P. t. ellioti have a unique epidemiological (12), cultural, and ecological heritage (39,40). However, morphological data for P. t. ellioti are very sparse, and the published studies are confounded by inclusion of specimens (41,42) collected outside its geographic range (6).…”

Section: Discussionmentioning

confidence: 97%

Evidence from Cameroon reveals differences in the genetic structure and histories of chimpanzee populations

Gonder

Locatelli

Ghobrial

et al. 2011

Proc. Natl. Acad. Sci. U.S.A.

105

110

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The history of the genus Pan is a topic of enduring interest. Chimpanzees (Pan troglodytes) are often divided into subspecies, but the population structure and genetic history of chimpanzees across Africa remain unclear. Some population genetics studies have led to speculation that, until recently, this species constituted a single population with ongoing gene flow across its range, which resulted in a continuous gradient of allele frequencies. Chimpanzees, designated here as P. t. ellioti, occupy the Gulf of Guinea region that spans southern Nigeria and western Cameroon at the center of the distribution of this species. Remarkably, few studies have included individuals from this region, hindering the examination of chimpanzee population structure across Africa. Here, we analyzed microsatellite genotypes of 94 chimpanzees, including 32 designated as P. t. ellioti. We find that chimpanzees fall into three major populations: (i) Upper Guinea in western Africa (P. t. verus); (ii) the Gulf of Guinea region (P. t. ellioti); and (iii) equatorial Africa (P. t. troglodytes and P. t. schweinfurthii). Importantly, the Gulf of Guinea population is significantly different genetically from the others, sharing a last common ancestor with the populations in Upper Guinea ∼0.46 million years ago (mya) and equatorial Africa ∼0.32 mya. Equatorial chimpanzees are subdivided into up to three populations occupying southern Cameroon, central Africa, and eastern Africa, which may have constituted a single population until ∼0.10-0.11 mya. Finally, occasional hybridization may be occurring between the Gulf of Guinea and southern Cameroon populations.chimpanzees | phylogenetics | population biology | microsatellites R evealing the histories of chimpanzees (Pan troglodytes) and bonobos (Pan paniscus) is of widespread and enduring interest due to their close relationship with humans. A recent proliferation of research shows that we are just beginning to unravel their complex histories (1), and even now, we still debate the number of species and subspecies belonging to the genus Pan. Most authorities agree that chimpanzees and bonobos should be classified as different species, with their ranges separated by the Congo River ( Fig. 1; ref. 2). Chimpanzees are frequently further divided into subspecies across tropical Africa (2, 3), but this classification is disputed (4). P. t. verus occupies the Upper Guinea region of western Africa (2, 3). The range of P. t. troglodytes extends through central Africa. P. t. schweinfurthii occupies eastern Africa (2, 3) and has been proposed to be split into two subspecies, P. t. schweinfurthii and P. t. marungensis, based on craniometric variation (5).The subspecies name P. t. ellioti (6), formerly P. t. vellerosus (7, 8), has been proposed for chimpanzees from the Gulf of Guinea region, which spans southern Nigeria and western Cameroon (9). However, relatively little is known about the genetic history of chimpanzees from this region, and some question their distinctiveness from adjacent populations (4). Ana...

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“…Chimpanzees in the wild are known to use natural stone and wooden hammers to crack open various nut species [14,30,[36][37][38][39][40]. Nut-cracking is a classic percussion behaviour whereby a nut is placed on a hard surface and a hammer is used to pound it until the nut breaks open.…”

Section: Introductionmentioning

confidence: 99%

Primate archaeology reveals cultural transmission in wild chimpanzees (Pan troglodytes verus)

Luncz

Wittig

Boesch

2015

Phil. Trans. R. Soc. B

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Recovering evidence of past human activities enables us to recreate behaviour where direct observations are missing. Here, we apply archaeological methods to further investigate cultural transmission processes in percussive tool use among neighbouring chimpanzee communities in the Taï National Park, Côte d'Ivoire, West Africa. Differences in the selection of nut-cracking tools between neighbouring groups are maintained over time, despite frequent female transfer, which leads to persistent cultural diversity between chimpanzee groups. Through the recovery of used tools in the suggested natal territory of immigrants, we have been able to reconstruct the tool material selection of females prior to migration. In combination with direct observations of tool selection of local residents and immigrants after migration, we uncovered temporal changes in tool selection for immigrating females. After controlling for ecological differences between territories of immigrants and residents our data suggest that immigrants abandoned their previous tool preference and adopted the pattern of their new community, despite previous personal proficiency of the same foraging task. Our study adds to the growing body of knowledge on the importance of conformist tendencies in animals.

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Chimpanzees use stone hammers in Cameroon

Abstract: BFU2004-02002) and by DURSI, Generalitat de Catalunya. We thank three anonymous referees for their comments and suggestions.

Cited by 79 publications

References 7 publications

Experimental studies illuminate the cultural transmission of percussive technologies inHomoandPan

Experimental studies illuminate the cultural transmission of percussive technologies inHomoandPan

Evidence from Cameroon reveals differences in the genetic structure and histories of chimpanzee populations

Primate archaeology reveals cultural transmission in wild chimpanzees (Pan troglodytes verus)

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