SOLUTIONS TO A TOOL-USE PROBLEM IN A PAIR OF CEBUS-APELLA

Eight experiments investigated tool-use in an adult male-female pair of capuchin monkeys, Cebus apella. Both subjects used sticks to probe into a closed box in order to extract honey contained therein, and both showed appropriate choices when selecting from an array of sticks of different thickness. The male readily modified sticks which were too thick, and used such sticks to rake in appropriate honey-dipping sticks lying out of reach. Neither subject constructed and used tools from elements which could be joined together, although the male per formed the joining component. The male, but not the female, straightened out bent wire in order to form a honey-dipping tool. The female showed less overall object-oriented behaviour, but profited from the male's tool-use. The results of some of the experiments suggest mental representation of the tool-using task and its solution, and indicate the importance of individual <<social strategies>>.