Macaques accidentally created stone fragments that bear a resemblance to some of the earliest stone artifacts produced by early hominins.
The study focuses on fresh analyzes of stone tools used by long-tailed macaques in Thailand’s Phang Nga National Park. These primates use stone tools to crack open hard-shelled nuts, often breaking their hammerstones and anvils in the process.
The collection of rock fragments resulting from this process is both significant in size and widely distributed across the terrain. Furthermore, many artifacts exhibit the same characteristics commonly associated with purpose-made stone tools found at some of the earliest archaeological sites in East Africa.
“The ability to deliberately make sharp stone flakes is seen as a key point in the evolution of hominins, and understanding how and when this happened is a big question that is usually investigated by studying the past artifacts and fossils. Our study shows that the manufacture of stone tools was not unique to humans and our ancestors,” said lead author Tomos Proffitt, a researcher at the Max Planck Institute for Evolutionary Anthropology.
“The fact that macaques use stone tools to process nuts is not surprising, because they also use tools to get access to different shellfish as well. What’s interesting is, in in doing so they unwittingly create a large archaeological record of their own that is partially indistinguishable from some hominin artifacts.
New insights into the evolution of stone tool technology
By comparing the accidental production of stone fragments produced by macaques to those from some of the earliest archaeological sites, the researchers were able to show that many of the artifacts produced by the monkeys were within the range of commonly associated among the first hominins.
Co-lead author Jonathan Reeves highlights: “The fact that these artifacts can be produced by nut cracking has implications for the range of behaviors we associate with sharps. blade in the archaeological record..”
Newly discovered macaque stone tools offer new insights into how early technology began in our earliest ancestors and that its origins may be linked to a similar nut cracking behavior that may have been more older than the current earliest archaeological record.
“Cracking nuts with stone hammers and anvils, similar to what some primates do today, has been suggested by some as a possible precursor to intentional stone tool making. This study, together with those previously published by our group, opens the door to identify such archaeological signatures in the future,” said Lydia Luncz, senior author of the study and head of the Technological Primates Research Group at the Max Planck Institute for Evolutionary Anthropology.
“This discovery shows how living primates can help researchers investigate the origins and evolution of tool use in our own species”
Reference: “Wild macaques challenge origins of deliberate tool making” by Tomos Proffitt, Jonathan S. Reeves, David R. Braun, Suchinda Malaivijitnond and Lydia V. Luncz, 10 March 2023, DOI: 10.1126/sciadv.ade8159