Preliminary assessment of methods used to demonstrate nut-cracking behavior to five captive chimpanzees (Pan troglodytes)

Chimpanzees acquire nut-cracking skills by observation and trial and error. Studies of captive chimpanzees have shown the effectiveness of a skilled demonstrator. We examined the effectiveness of 3 live demonstration forms from which subjects could learn nut-cracking skills: a video of proficient conspecifics, human demonstration and the presence of a skilled conspecific performing the task. A male subject did not learn to crack open nuts after viewing a video of proficient conspecifics but quickly learned the skill following a demonstration by a human facilitator. Subsequently, 4 female chimpanzees were given the opportunity to learn the skill from the now proficient male, as well as from a video and human demonstration, but failed to do so.