Modern Monkeys' Stone Tools Challenge Human Evolution Timeline

Stone fragments resembling ancient stone tools made by prehistoric humans were actually made unintentionally by old world monkeys living in Thailand. This discovery calls into question the identification of at least some ancient stone tools as human cutting or scraping objects. The ability to intentionally make sharp stone flakes is seen as a crucial point in the evolution of hominins, and understanding how and when this occurred is a huge question that is typically investigated through the study of past artifacts and fossils.