New archaeological evidence suggests that Brazilian capuchins have been using stone tools to crack open cashew nuts for at least 700 years, and the new research paper asks whether human behaviour was influenced through watching the monkeys. Researchers say, to date, they have found the earliest archaeological examples of monkey tool use outside of Africa. In their paper, published in Current Biology, they suggest it raises questions about the origins and spread of tool use in New World monkeys and, controversially perhaps, prompts us to look at whether early human behaviour was influenced by their observations of monkeys using stones as tools. The research was led by Dr Michael Haslam of the University of Oxford, who in previous papers presents archaeological evidence showing that wild macaques in coastal Thailand used stone tools for decades at least to open shellfish and nuts.