title: Cultural differences in ant-dipping tool length between neighbouring chimpanzee communities at Kalinzu, Uganda.
abstract: Cultural variation has been identified in a growing number of animal species ranging from primates to cetaceans. The principal method used to establish the presence of culture in wild populations is the method of exclusion. This method is problematic, since it cannot rule out the influence of genetics and ecology in geographically distant populations. A new approach to the study of culture compares neighbouring groups belonging to the same population. We applied this new approach by comparing ant-dipping tool length between two neighbouring communities of chimpanzees (Pan troglodytes schweinfurthii) in the Kalinzu Forest, Uganda. Ant-dipping tool length varies across chimpanzee study sites in relation to army ant species (Dorylus spp.) and dipping location (nest vs. trail). We compared the availability of army ant species and dipping tool length between the two communities. M-group tools were significantly longer than S-group tools, despite identical army ant target species availabilities. Moreover, tool length in S-group was shorter than at all other sites where chimpanzees prey on epigaeic ants at nests. Considering the lack of ecological differences between the two communities, the tool length difference appears to be cultural. Our findings highlight how cultural knowledge can generate small-scale cultural diversification in neighbouring chimpanzee communities.
authors.affiliation: 1] Anthropological Institute and Museum, University of Zurich, Winterthurerstrasse 190, 8057 Zürich, Switzerland [2] Department of Archaeology and Anthropology, University of Cambridge, Pembroke Street, CB2 3QG Cambridge, United Kingdom.
authors.forename: Kathelijne
authors.initials: K
authors.lastname: Koops
authors.affiliation: Institut für Biologie, Arbeitsgruppe Funktionelle Biodiversität, Freie Universität, Königin-Luise-Strasse 1-3, 14195 Berlin, Germany.
authors.forename: Caspar
authors.initials: C
authors.lastname: Schöning
authors.affiliation: Primate Research Institute, Kyoto University, Aichi 484-8506, Inuyama, Japan.
authors.forename: Mina
authors.initials: M
authors.lastname: Isaji
authors.affiliation: Primate Research Institute, Kyoto University, Aichi 484-8506, Inuyama, Japan.
authors.forename: Chie
authors.initials: C
authors.lastname: Hashimoto
mesh_terms: D000818:Animals; D001000:Ants; D004463:Ecology; D017753:Ecosystem; D005247:Feeding Behavior / Q000502:physiology*; D065928:Forests; D005843:Geography; D002679:Pan troglodytes / Q000502:physiology*; D011235:Predatory Behavior / Q000502:physiology*; D053001:Tool Use Behavior / Q000502:physiology*; D014454:Uganda