In Thailand, researchers from the Max Planck Institute for Evolutionary Anthropology discovered artefacts made by ancient monkeys that resemble stone tools that were once believed to have been intentionally made by early hominins. Sharp-edged stone tools were previously supposed to signify the beginning of purposeful stone tool manufacturing, which is one of the defining and distinctive features of hominid evolution. The study is based on recent examinations of stone tools made by long-tailed macaques in Thailand’s Phang Nga National Park. These monkeys break open nuts with the use of stone tools. The monkeys frequently smash their anvils and hammerstones in the process. The resulting collection of broken stones is sizable and dispersed throughout the countryside. In addition, many of these artefacts share the same traits that can be used to distinguish deliberately created stone tools from other types of stone tools in some of the earliest archaeological sites in East Africa. Understanding how and when this occurred is a big subject that is often studied through the study of ancient artefacts and fossils, which is viewed as an important stage in the evolution of hominins. Tomos Proffitt, a researcher at the Max Planck Institute for Evolutionary Anthropology and the study’s lead author, said, “Our study demonstrates that stone tool production is not exclusive to humans and our ancestors. The fact that these macaques process nuts with stone tools is not surprising, as they also use tools to access a variety of shellfish. It’s interesting because they unintentionally create a sizable archaeological record of their own that is partially identical to some artefacts from early hominins. The researchers were able to demonstrate that many of the artefacts generated by monkeys fall within the range of those often associated with early hominins by comparing the inadvertently created stone fragments formed by the macaques with those from some of the earliest archaeological sites. The fact that these artefacts can be made through nut breaking has ramifications for the variety of behaviours we identify with sharp-edged flakes in the archaeological record, according to co-lead author Jonathan Reeves. The recently discovered macaque stone tools provide fresh insights into how our earliest ancestors may have begun using technology. They suggest that this origin may have been connected to comparable nut-cracking behaviour that may be much older than the earliest archaeological records.
“Using stone hammers and anvils to crack nuts, like certain monkeys do today, has been proposed by some as a potential predecessor to the intentional creation of stone tools. This study opens the possibility of later being able to recognise such an archaeological signature, along with earlier ones published by our group.