Examining interactions among sympatric primate species can provide interesting information about competition, cooperation, and avoidance between those species. Those interactions can be neutral, positive, or negative for the species involved. Capuchin monkeys are medium-sized primates that can encounter both larger and smaller primates in their varied habitats. Gracile capuchins (Cebus) are reported to present different types of interactions with other primates. Interactions with howler monkeys frequently include physical aggression, while interactions with spider monkeys are mostly threats and chases. Moreover, interaction types are not consistent across populations. Among robust capuchins (Sapajus spp.), however, no reports have been published. Here we describe and classify encounters of Sapajus libidinosus and S. nigritus with Alouatta caraya, A. guariba, Brachyteles arachnoides, and Callithrix jacchus in three sites in the environments of Cerrado, Caatinga (savannah-like), and Atlantic forest, and compare the interaction patterns among sites and different group sizes. The latter is a factor that can influence the outcome, and we expected capuchins in larger groups to be more aggressive toward other primates. Our results of 8421 h of total contact with the capuchin groups show that, indeed, capuchins in sites with larger groups presented aggressive interactions with higher frequency. However, the other species’ body size also seems important as smaller primates apparently avoided capuchins, and interactions with the larger muriquis were mostly neutral for the capuchin. Capuchins showed neutral or aggressive behaviors toward howler monkeys, with differences between the rainforest and savannah groups. We found that robust capuchins can present aggressive interactions even to primates larger than themselves and that aggressive behavior was the most common response in populations living in larger groups and drier environments.

检查同域灵长类动物之间的相互作用可以提供有关这些物种之间竞争、合作和回避的有趣信息。对于所涉及的物种，这些相互作用可以是中性的、积极的或消极的。卷尾猴是中型灵长类动物，可以在不同的栖息地遇到较大和较小的灵长类动物。据报道，纤细卷尾猴 ( Cebus ) 与其他灵长类动物表现出不同类型的相互作用。与吼猴的互动通常包括身体攻击，而与蜘蛛猴的互动主要是威胁和追逐。此外，交互类型在不同人群中并不一致。在强壮的卷尾猴（Sapajusspp.)，然而，尚未发表任何报告。在这里，我们描述和分类Sapajus libidinosus和S. nigritus与Alouatta caraya、A. guariba、Brachyteles arachnoides和Callithrix jacchus 的相遇。在塞拉多、卡廷加（类热带草原）和大西洋森林环境中的三个站点中，比较站点和不同群体规模之间的交互模式。后者是影响结果的一个因素，我们预计较大群体中的卷尾猴对其他灵长类动物更具攻击性。我们与卷尾猴群总接触时间为 8421 小时的结果表明，事实上，群落较大的地点的卷尾猴表现出更高频率的积极互动。然而，其他物种的体型似乎也很重要，因为较小的灵长类动物显然避开了卷尾猴，而与较大的鼠类的相互作用对卷尾猴来说大多是中性的。卷尾猴对吼猴表现出中性或攻击性的行为，热带雨林和大草原组之间存在差异。