Cumulative culture in nonhumans : overlooked findings from Japanese monkeys?

The authors thank Corpus Christi College (Cambridge) for funding DS’s visit to Koshima and Prof. Tetsuro Matsuzawa for funding WCM’s visit to Koshima.Cumulative culture, generally known as the increasing complexity or efficiency of cultural behaviors additively transmitted over successive generations, has been emphasized as a hallmark of human evolution. Recently, reviews of candidates for cumulative culture in nonhuman species have claimed that only humans have cumulative culture. Here, we aim to scrutinize this claim, using current criteria for cumulative culture to re-evaluate overlooked qualitative but longitudinal data from a nonhuman primate, the Japanese monkey (Macaca fuscata). We review over 60 years of Japanese ethnography of Koshima monkeys, which indicate that food-washing behaviors (e.g., of sweet potato tubers and wheat grains) seem to have increased in complexity and efficiency over time. Our reassessment of the Koshima ethnography is preliminary and nonquantitative, but it raises the possibility that cumulative culture, at least in a simple form, occurs spontaneously and adaptively in other primates and nonhumans in nature.Publisher PDFPeer reviewe

External ballistics of Pleistocene hand-thrown spears: experimental performance data and implications for human evolution

The appearance of weaponry - technology designed to kill - is a critical but poorly established threshold in human evolution. It is an important behavioural marker representing evolutionary changes in ecology, cognition, language and social behaviours. While the earliest weapons are often considered to be hand-held and consequently short-ranged, the subsequent appearance of distance weapons is a crucial development. Projectiles are seen as an improvement over contact weapons, and are considered by some to have originated only with our own species in the Middle Stone Age and Upper Palaeolithic. Despite the importance of distance weapons in the emergence of full behavioral modernity, systematic experimentation using trained throwers to evaluate the ballistics of thrown spears during fight and at impact is lacking. This paper addresses this by presenting results from a trial of trained javelin athletes, providing new estimates for key performance parameters. Overlaps in distances and impact energies between hand-thrown spears and spearthrowers are evidenced, and skill emerges as a signifcant factor in successful use. The results show that distance hunting was likely within the repertoire of hunting strategies of Neanderthals, and the resulting behavioural flexibility closely mirrors that of our own specie