title: Distance-decay effect in stone tool transport by wild chimpanzees.
abstract: Stone tool transport leaves long-lasting behavioural evidence in the landscape. However, it remains unknown how large-scale patterns of stone distribution emerge through undirected, short-term transport behaviours. One of the longest studied groups of stone-tool-using primates are the chimpanzees of the Taï National Park in Ivory Coast, West Africa. Using hammerstones left behind at chimpanzee Panda nut-cracking sites, we tested for a distance-decay effect, in which the weight of material decreases with increasing distance from raw material sources. We found that this effect exists over a range of more than 2 km, despite the fact that observed, short-term tool transport does not appear to involve deliberate movements away from raw material sources. Tools from the millennia-old Noulo site in the Taï forest fit the same pattern. The fact that chimpanzees show both complex short-term behavioural planning, and yet produce a landscape-wide pattern over the long term, raises the question of whether similar processes operate within other stone-tool-using primates, including hominins. Where hominin landscapes have discrete material sources, a distance-decay effect, and increasing use of stone materials away from sources, the Taï chimpanzees provide a relevant analogy for understanding the formation of those landscapes.
authors.affiliation: Primate Archaeology Research Group, School of Archaeology, University of Oxford, Oxford, UK lydia.luncz@rlaha.ox.ac.uk.
authors.forename: Lydia V
authors.identifier: 0000-0003-2972-4742
authors.initials: LV
authors.lastname: Luncz
authors.affiliation: Primate Archaeology Research Group, School of Archaeology, University of Oxford, Oxford, UK.
authors.forename: Tomos
authors.initials: T
authors.lastname: Proffitt
authors.affiliation: Department of Primatology, Max Planck Institute for Evolutionary Anthropology, Leipzig, Germany.|Institute of Biology, University of Leipzig, Leipzig, Germany.
authors.forename: Lars
authors.initials: L
authors.lastname: Kulik
authors.affiliation: Primate Archaeology Research Group, School of Archaeology, University of Oxford, Oxford, UK.
authors.forename: Michael
authors.identifier: 0000-0001-8234-7806
authors.initials: M
authors.lastname: Haslam
authors.affiliation: Department of Primatology, Max Planck Institute for Evolutionary Anthropology, Leipzig, Germany.|Taï Chimpanzee Project, Centre Suisse de Recherches Scientifiques, Abidjan, Côte d'Ivoire.
authors.forename: Roman M
authors.initials: RM
authors.lastname: Wittig
mesh_terms: D000354:Africa, Western; D000818:Animals; D002679:Pan troglodytes; D053001:Tool Use Behavior
keywords: chimpanzees; distance-decay effect; primate archaeology; stone tools; transport