Chimpanzee accumulative stone throwing

Abstract

The study of the archaeological remains of fossil hominins must rely on reconstructions to elucidate the behaviour that may have resulted in particular stone tools and their accumulation. Comparatively, stone tool use among living primates has illuminated behaviours that are also amenable to archaeological examination, permitting direct observations of the behaviour leading to artefacts and their assemblages to be incorporated. Here, we describe newly discovered stone tool-use behaviour and stone accumulation sites in wild chimpanzees reminiscent of human cairns. In addition to data from 17 mid- to long-term chimpanzee research sites, we sampled a further 34 Pan troglodytes communities. We found four populations in West Africa where chimpanzees habitually bang and throw rocks against trees, or toss them into tree cavities, resulting in conspicuous stone accumulations at these sites. This represents the first record of repeated observations of individual chimpanzees exhibiting stone tool use for a purpose other than extractive foraging at what appear to be targeted trees. The ritualized behavioural display and collection of artefacts at particular locations observed in chimpanzee accumulative stone throwing may have implications for the inferences that can be drawn from archaeological stone assemblages and the origins of ritual sites.

The impact of endogenous content, replicates and pooling on genome capture from faecal samples

“…This study employed 18 faecal samples derived from 17 individuals previously collected as a part of the Pan African Programme: The Cultured Chimpanzee project (PanAf; http://panafrican.eva.mpg.de; Kühl et al., ; Vaidyanathan, ). All PanAf chimpanzee faecal samples are collected from unhabituated chimpanzees from up to 3‐day‐old faecal piles using a two‐step ethanol‐silica preservation method (Nsubuga et al., ).…”

Stone tool transport by wild Burmese long-tailed macaques (Macaca fascicularis aurea)

“…As part of this behaviour, they transport and accumulate stones in ways that mirror other primates' tool use sites (Huffman and Quiatt, 1986;Quiatt and Huffman, 1993). Similarly, some West African chimpanzees (Pan troglodytes verus) have been reported to throw and bang stones against trees, again resulting in an observable accumulation (Kühl et al, 2016).…”

Seasonal Variation in Physiology Challenges the Notion of Chimpanzees (Pan troglodytes verus) as a Forest-Adapted Species

“…This assumption persists despite little effort to define potential chimpanzee environmental limits (McGrew et al, 1981;Kortlandt, 1983), and the predominant focus of chimpanzee research undertaken in wetter, more forested habitats (e.g., forested research sites significantly outnumber open habitat sites, e.g., 3 of 17 sites in Kühl et al, 2016). Conversely, however, others have argued that the extent of savanna habitats within the chimpanzee biogeographical range indicates that this is a habitat to which they are equally suited (Kortlandt, 1983).…”