title: Distribution of potential suitable hammers and transport of hammer tools and nuts by wild capuchin monkeys.
abstract: Selection and transport of objects to use as tools at a distant site are considered to reflect planning. Ancestral humans transported tools and tool-making materials as well as food items. Wild chimpanzees also transport selected hammer tools and nuts to anvil sites. To date, we had no other examples of selection and transport of stone tools among wild nonhuman primates. Wild bearded capuchins (Cebus libidinosus) in Boa Vista (Piauí, Brazil) routinely crack open palm nuts and other physically well-protected foods on level surfaces (anvils) using stones (hammers) as percussive tools. Here we present indirect evidence, obtained by a transect census, that stones suitable for use as hammers are rare (study 1) and behavioral evidence of hammer transport by twelve capuchins (study 2). To crack palm nuts, adults transported heavier and harder stones than to crack other less resistant food items. These findings show that wild capuchin monkeys selectively transport stones of appropriate size and hardness to use as hammers, thus exhibiting, like chimpanzees and humans, planning in tool-use activities.
authors.affiliation: Istituto di Scienze e Tecnologie della Cognizione, Consiglio Nazionale delle Ricerche, Via Aldrovandi 16B, 00161 Rome, Italy. elisabetta.visalberghi@istc.cnr.it
authors.forename: Elisabetta
authors.initials: E
authors.lastname: Visalberghi
authors.forename: Noemi
authors.initials: N
authors.lastname: Spagnoletti
authors.forename: Eduardo D
authors.initials: ED
authors.lastname: Ramos da Silva
authors.forename: Fabio R D
authors.initials: FR
authors.lastname: Andrade
authors.forename: Eduardo
authors.initials: E
authors.lastname: Ottoni
authors.forename: Patricia
authors.initials: P
authors.lastname: Izar
authors.forename: Dorothy
authors.initials: D
authors.lastname: Fragaszy
mesh_terms: D000818:Animals; D001938:Brazil; D002428:Cebus / Q000502:physiology*; D005247:Feeding Behavior / Q000502:physiology*; D009754:Nuts; D019370:Observation; D053001:Tool Use Behavior / Q000502:physiology*