This paper reports the behavior of the black capped capuchin monkey, Cebus apella, using tools to break seeds of Syagrus romanzoffianum in search of coleoptera larvae that live inside. The study area was the Parque Municipal Arthur Thomas (85,47 ha) located in the city of Londrina, Paraná state. In one year of study, using the ad libitum method, the monkeys were observed using rocks pretty much in the same way as if they were hammer and anvil. Individuais of both sexes including adults, subadults and juveniles with more than two years of age, were involved in such activity. The behavior of the animais consisted of they place the seeds on a large rock in the ground, and using a smaller rock which was hold among the hands, the seeds were beaten repeatedly until breaking. Then they ate the larvae and/or endosperm. The use of tools is thought to have brought benefits to the animais by allowing the access to a source of food that would not normally be used.
Primate; Cebidae; Cebus apella; behavior