Monkeys in Thailand may be challenging the history of human evolution through their nut-cracking abilities.
New research from the Max Planck Institute for Evolutionary Anthropology in Germany describes stone-tool resembling artifacts made by monkeys in Thailand that may suggest the first human use of stone tools was not intentional.
The researchers studied long-tailed macaques in Phang Nga National Park in Thailand that were found to be cracking open hard-shelled nuts using stone tools..
The monkeys were often observed to break hammerstones and anvils to get to the nuts, which would result in broken stones scattered all around the landscape.
Through comparison to the earliest record of stone tools, many of these “accidental” broken stones appeared to have similar characteristics of stone tools often found in some of the earliest archaeological sites in East Africa.
“The fact that these macaques use stone tools to process nuts is not surprising, as they also use tools to gain access to various shellfish as well,” said lead author Tomos Proffitt, a researcher at the Max Planck Institute, in a press release. “What is interesting is that in doing so they accidently produce a substantial archaeological record of their own that is partly indistinguishable from some hominin artifacts.
Prior to this discovery, sharp-edged tools were believed to be the first stone tools intentionally made by humans, but this research challenges that, as well as the understanding of an aspect of human evolution.
“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. Our study shows that stone tool production is not unique to humans and our ancestors,” said Proffitt.
According to the Smithsonian Institute, the first stone toolmaking was at least 2.6 million years ago and was supposedly by early humans.
This new research involving monkeys, however, could offer new insights into a potentially earlier archeological record of the first stone tools.
“This study, along with previous ones published by our group, opens the door to being able to identify such an archaeological signature in the future,” said Lydia Luncz, senior author of the study and head of the Technological Primates Research Group at the Max Planck Institute. “This discovery shows how living primates can help researchers investigate the origin and evolution of tool use in our own lineage.”