Predatory attack on a bearded capuchin monkey by a Boa constrictor.

Predation influences foraging strategies, as primates must avoid being preyed on while feeding. Some populations of capuchin monkeys are the only neotropical primates that customarily use the ground for nut-cracking. This time-consuming and focus-demanding foraging activity may increase susceptibility to predation events. However, there is currently no data on predation in tool-using Sapajus populations. We report a snake's (Boa constrictor) predatory attack on a bearded capuchin monkey (S. libidinosus) in a tool-using population, as well as the other monkeys' alarm calling and threat displays. We confirm these monkeys' predation vulnerability and discuss how they balance foraging requirements with predation risk.