Capuchin monkeys are known for their cognitive abilities, including object manipulation and use of a variety of tools. The hooded capuchin (Sapajus cay) is the only repre-sentative of its genus found in Paraguay and is critically
understudied in the country. This paper reports on preliminary observations of a group of hooded capuchins, in Rancho Laguna Blanca, San Pedro, Paraguay, using two different first-order object manipulation techniques to open the seeds
of the tree Cariniana estrellensis (Lecythidaceae). Some indi-viduals held the seed in both hands and stood bipedally, using their entire body weight to smash the seed against a branch. The more commonly observed technique involved the mon-keys holding the seed in one hand and repeatedly striking the branch with the fruit until they could extract the seed. Only adults were ever observed to be successful in opening the fruits.