An experimental study with captive individuals and study of video recordings of wild monkeys explored whether and how tufted capuchin monkeys use onehand to hold one or more objects with multiple grips (compound grips). A task designed to elicit compound grip was presented to five captive tufted capuchin monkeys (Sapajus spp). The monkeys held one to four balls in onehand and dropped the balls individually into a vertical tube. Multiple simple grips and independent digit movements enabled separate control of multiple objects in one hand. Monkeys always supported the wrist on the horizontal edge of the tube before releasing the ball. Increasing the number of balls decreased the likelihood that the monkeys managed the task. Wild bearded capuchins (Sapajus libidinosus) used compound grips spontaneously to store multiple food items. Compound grips have been described in macaques, gorillas, chimpanzees, and humans, and now in a New World primate. We predict that any primate species that exhibits precision grips and independent digit movement can perform compound grips. Our findings suggest many aspects of compound grip that await investigation.

中文翻译：

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簇绒卷尾猴（Sapajus spp和Sapajus libidinosus）的复合抓地力。

一项关于圈养个体的实验研究以及对野生猴子的视频记录的研究探索了簇绒的卷尾猴是否以及如何用一只手握住一个或多个具有多个抓握（复合抓握）的物体。向五只圈养的卷尾猴（Sapajus spp）提出了旨在引起复合抓地力的任务。猴子单手握住一到四个球，然后将这些球分别丢入垂直管中。多个简单的手柄和独立的手指移动功能使一只手可以分别控制多个对象。在释放球之前，猴子总是将腕部支撑在管的水平边缘上。增加球的数量会降低猴子完成任务的可能性。野生胡子卷尾猴（Sapajus libidinosus）自发地使用复合夹子来存储多种食品。在猕猴，大猩猩，黑猩猩和人类中，以及现在在新世界的灵长类动物中，已经描述了复合握持。我们预测，任何表现出精确抓握和独立手指移动的灵长类动物都可以执行复合抓握。我们的发现表明，复合抓地力的许多方面有待研究。