Discovering and learning tool-use for fishing honey by captive chimpanzees

Wild chimpanzees commonly use sticks to fish for termites, ants or honey. This ability seems to be socially transmitted to juveniles by their mothers across generations. In a natural environment, the limited visibility of this behavior with regards to the extent of stick's insertion and about the success or failure in fishing hinders the study of the underlying learning processes. This study explores the discovery and learning of tool use for fishing honey in an artificial hive by a group of four captive chimpanzees. The discovery of tool use was accidental and coactive. The speed with which the group of experimentally naive chimpanzees discovered and learned tool use suggests that wild chimpanzees of different populations independently discovered the fishing behavior. The alpha male and his ally learned before the subordinates. Here, trial-and-error learning was, as in monkeys, the main process allowing the acquisition of the tool-use technique. However, the observation of conspecifics allowed the orientation of the experimentation by the selection of clues. As suggested by Tomaselloet al. (1987). it is the understanding of the function of the tool,i.e. the cause-effect relations between the action of the demonstrator, the type of tool and the task to accomplish which confer to chimpanzees and advantage over monkeys.