RESEARCH ARTICLE Diversity of Nutcracking Tool Sites Used by Sapajus libidinosus in Brazilian Cerrado FRANCISCO DYONÍSIO C. MENDES 1,2 *, RAPHAEL MOURA CARDOSO 2,3 , EDUARDO B. OTTONI 3 , PATRÍCIA IZAR 3 , DANIELL NUNES A. VILLAR 2 , AND ROGÉRIO F. MARQUEZAN 4,5 1 Departamento de Processos Psicológicos Básicos, Universidade de Brasília, Brasília, Brazil 2 Departamento de Psicologia, Pontifícia Universidade Católica de Goiás, Goiânia, Brazil 3 Departamento de Psicologia Experimental, Universidade de São Paulo, São Paulo, Brazil 4 Departamento de Psicologia, Centro Universitário UNIRG, Gurupi, Brazil 5 Departamento de Medicina, Universidade Federal do Tocantins, Palmas, Brazil Cracking nuts with tools is a behavior documented in a small number of populations of tufted capuchins, mainly in semi-arid Caatinga and Caatinga–Cerrado transitional environments of northeastern Brazil. Only one of these populations inhabits the less arid Cerrado in Central Brazil, where environments are composed of a heterogeneous mosaic of fields, savannas and forest formations. We conducted surveys in 10 of 20 localities where nutcracking by capuchins was reported by the local inhabitants in the Cerrrado of Northern Goiás and Tocantins. Our purpose was to evaluate nutcracking sites (anvils and associated hammers and nuts) based on indirect evidence of extensive pounding of nuts and seeds. Nutcracking was confirmed at all 10 surveyed localities. A total of 270 sites were identified. Surveyed localities included areas that were ecologically similar to those where capuchins crack nuts in Caatinga, as well as less arid localities with more typical Cerrado habitat. Anvils and hammers were made of materials including quartz, limestone, sandstone and wood, and displayed a wider range of sizes (i.e., 60–3,750 g for hammers’ weight) than reported at previously studied localities. Nuts of seven genera were found in association with anvils and hammers. We conclude that nutcracking by capuchins are not restricted to arid environments and argue that the occurrence and diversity of nutcracking tool sites result from complex interactions of environmental variables (e.g., availability of food and mineral resources, density of canopy cover) and social variables (e.g., spatial cohesiveness and tolerance among group members) that need to be examined through long-term research of habituated groups. Localities in the Cerrado of Northern Goiás and Tocantins vary considerable in the ecological conditions faced by wild groups, and therefore offer the opportunity to examine these interactions. Am. J. Primatol. 77:535–546, 2015. © 2015 Wiley Periodicals, Inc. Key words: nutcracking; capuchin monkeys; tool use; Cerrado INTRODUCTION In a thorough review of tool use and laterality in chimps, bonobos and capuchin monkeys, McGrew and Marchant [1997] concluded that “naturalistic tool use is the norm for chimpanzees and the exception for bonobos and capuchins” (page 795), and hypothesized that lack of records for wild capuchins could be due to “sparse observation, lack of habituation, and arboreality” (page 803). Since then, examples of spontaneous tool use by wild tufted capuchin monkeys (Sapajus sp. [Lynch Alfaro et al., 2012]) have included the use of sticks to probe insect nests and dislodge lizards from rock cracks [Mannu & Ottoni, 2009] and to fish for termites [Souto et al., 2011] and the use of stone throwing as a form of communication [Falótico & Ottoni, 2013; Moura, 2007]. The vast majority of reported cases, however, refer to the pounding of stones to crack open encapsulated fruit (nutcracking [Fragaszy et al., 2004a; Ottoni & Izar, 2008]), a behavior that is shared with chimpanzees and our own species [Fragaszy et al., 2010]. The rarity of previous records was due, at least in part, to limited efforts to observe tufted capuchins living in dry habitats. Conflicts of interest: None.  Correspondence to: Dr. Francisco Dyonísio C. Mendes (Dida), Departamento de Processos Psicológicos Básicos, Instituto de Psicologia, Universidade de Brasília, ICC Sul-sala 022/4, Campus Darcy Ribeiro, Brasília, DF-Brazil, CEP: 70910-900. E-mail: didamendes01@gmail.com Received 6 February 2014; revised 3 December 2014; revision accepted 9 December 2014 DOI: 10.1002/ajp.22373 Published online 12 February 2015 in Wiley Online Library (wileyonlinelibrary.com). American Journal of Primatology 77:535–546 (2015) © 2015 Wiley Periodicals, Inc.