Chimpanzees use stone hammers in Cameroon

ago [12]; however, the standard error is 65,000 years at these sample sizes. The MLS sequence documents a greater diversity among the European Neandertals than previously estimated. In particular, the MLS and MEZ sequences appear separated from a cluster of sequences from Germany and Croatia. All sequences in the cluster share two derived alleles, 16078G and 16154C. The analysis of Neandertal genetic diversity confirms that Neandertals were separated from modern humans by several fixed mtDNA differences. However, their internal diversity was rather large. Even members of the same population, such as FE1 and FE2, could differ substantially, and haplotypes in geographically extreme populations also seem to be genetically differentiated. This raises questions concerning the demographic and evolutionary history of Neandertals. and BFU2004-02002) and by DURSI, Generalitat de Catalunya. We thank three anonymous referees for their comments and suggestions. Supplemental data Supplemental data and experimental procedures are available at Towards a theory of modern human origins: Geography, demography, and diversity in recent human evolution. Am. The Neandertal type site revisited; interdisciplinary investigations of skeletal remains from the Neander Valley, Germany. (2003). Evidence for a genetic discontinuity between Neandertals and 24,000-year-old anatomically modern Europeans. Proc. Modern humans did not admix with Neanderthals during their range expansion into Europe. (2005). Neandertal evolutionary genetics: mitochondrial DNA data from the iberian peninsula. (2006). Mitochondrial DNA of an Iberian Neandertal suggests a population affinity with other European Neandertals. Curr. All studied chimpanzee populations use tools, with differences in behavioural repertoires between populations implying significant cultural variation, but the only major known tool-using behaviour that is geographically confined to a single contiguous region is the absence of nut-cracking in all populations east of the N'Zo-Sassandra River in Cote d'Ivoire [1–4]. Nut-cracking is the paradigmatic example of a nutritionally high-value, socially transmitted tradition and here we report that chimpanzees in the Ebo forest, Cameroon, more than 1700 km east of the previously proposed riverine 'information barrier' in Cote d'Ivoire, have been observed to crack the hard shelled nuts of Coula edulis with stones used as hammers, so as to access the nutrient-rich seeds. This observation challenges the existing model of the cultural diffusion of nut-cracking behaviour [2,3] by implying that it has been invented on multiple occasions; alternatively, if nut-cracking is an ancient trait in the western chimpanzee populations then there have been extinctions of the behaviour in areas between the N'Zo-Sassandra River and the Ebo forest. The …