Chimpanzee Stone Age (IMAGE) Max-Planck-Gesellschaft Caption A typical stone hammer showing deep wear used by chimpanzees in the Tai forest to crack Panda nuts. Credit Max Planck Institute of Evolutionary Anthropology Usage Restrictions None License Licensed content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.