Abstract Sapajus libidinosus members of the Pedra Furada group, living in the Serra da Capivara National Park, use stone tools in a wider variety of behaviors than any other living animal, except humans. To rescue the evolutionary history of the Caatinga S. libidinosus and identify factors that may have contributed to the emergence and maintenance of their tool-use culture, we conducted fieldwork seasons to obtain biological samples of these capuchin monkeys. UsingCYTBsequences, we show a discrete but constant population growth from the beginning of the Holocene to the present, overlapping the emergence of the Caatinga biome. Our habitat suitability reconstruction reports the presence of plants whose hard fruits, seeds, or roots are processed by capuchins using tools. TheS. libidinosusindividuals in the Caatingawere capable of dynamically developing and maintaining their autochthonous culture thanks to: a) cognitive capacity to generate and execute innovation under selective pressure; b) tolerance favoring learning and cultural inheritance; c) an unknown genetic repertoire that underpins the adaptive traits; d) a high degree of terrestriality; e) presence and abundance of natural resources, which makes some places “hot spots” for innovation, and cultural diversification within a relatively short time. group Park animal humans S tooluse tool monkeys UsingCYTBsequences present biome fruits seeds TheS pressure b inheritance c traits d terrestriality e resources hot spots time

Capuchin monkeys, Sapajus Kerr, 1792, are known for their flexible behavior, including tool use, and their ability to survive in urban forests. We observed capuchin juveniles using wood as hammer and anvil and different materials as sponges (four tool-use events) in two geographically distinct urban populations in Brazil, in 2012: two in Goiânia, Central Brazil and two in Foz do Iguaçu, Southern Brazil. In Goiânia, a male used a detached tree branch as a hammer and a buttress root as an anvil to pound a seed of Terminalia Linnaeus. Another male used a small branch with leaves as a dipping tool to access water inside a tree trunk hole. In Foz do Iguaçu, the capuchins used a small branch and a piece of bread to obtain water by dipping them into tree trunk holes. This latter event might be interpreted as a case of self-control, with a familiar food item used as a tool to reach a resource that is difficult to access otherwise. Our observations contribute to the knowledge on the tool-kit of capuchins and we propose that these urban populations should be conserved for scientific evaluations of behavioral flexibility in non-human primates.

According to behavioural ecology, infanticide by males would be an adaptive reproductive strategy because it allows faster fertilization of the females and reduces investment in unrelated offspring. Critics of this view indicate the lack of evidence of the behaviour for several primate species, hence the relevance of reports of observed infanticide events. Here we report a case of infant killing in a free-ranging group of tufted capuchin monkeys (Cebus nigritus).

Según la ecología del comportamiento, el infanticidio realizado por los machos podría ser una estrategia reproductiva adaptativa porque permite mayor rapidez en la fertilización de las hembras y reduce la inversión en crías no emparentadas. Los críticos de este punto de vista advierten sobre la falta de evidencia de este comportamiento en varias especies de primates, de ahí la relevancia de los relatos de observación de eventos de infanticidio. En este trabajo reportamos un caso de infanticidio en un grupo silvestre de monos capuchinos (Cebus nigritus).

Nossa pesquisa tem como objetivo estudar o desenvolvimento dos infantes e juvenis de um grupo de macacos-prego (Cebus apella) em condição de semiliberdade, com ênfase nos comportamentos manipulativos. No presente estudo, relacionamos o aparecimento do uso de instrumentos para quebra de cocos com a brincadeira social e com a brincadeira com objetos. A brincadeira social ocorreu predominantemente em infantes e juvenis. A brincadeira com objetos, muitas vezes indistinguível das atividades exploratórias, aumentou durante o primeiro ano de vida. A manipulação exploratória de pedras constitui uma oportunidade importante para a aprendizagem individual, por tentativa-e-erro, do uso de instrumentos para quebrar cocos, que surge entre o segundo e o terceiro anos de vida. A brincadeira social parece facilitar a tolerância entre os sujeitos, o que favoreceria a aprendizagem por observação dos episódios de quebra.

The aim of our research is the study of the development of young tufted capuchin monkeys (Cebus apella) from a semi-free group, with an emphasis in manipulative behaviors. In the present study, we discuss the relations between the appearance of tool-use in nutcracking and social and object play. Social play occured mainly among infant and juvenile subjects. Object play is often indistinct from exploratory activities and increased during the first year of life. The appearance of the use of tools for cracking nuts, between the second and the third year, is related to exploratory manipulation because of its importance for trial-and-error learning. Social play may facilitate tolerance among subjects and hence favour the observational learning of nutcracking.