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Abstract
Compound grips (the use of one hand to hold one or more objects with multiple grips) have been described in macaques, gorillas, chimpanzees, and humans, but have not been explored in any New World primate. Capuchin monkeys use both power and precision grips, and we predicted they use compound grips as well. A task to prompt compound grip was presented to captive tufted capuchin monkeys. All monkeys held 1-4 balls in one hand and dropped them individually into a tube. Wild capuchins were also filmed using compound grips naturally. Regarding the results of both samples, we conclude that capuchin monkeys hold and move multiple objects in one hand, and simple grips and independent digit movements support separate control of objects in one hand. These findings contribute to our current understanding of comparative primate dexterity, and challenge prior knowledge of the capabilities of capuchin monkeys.