Stone flakes are found by archeologists showing a window into the early human way of creating tools specifically to hunt – its deliberate sharp edges show skill and intent for its purpose. However, it may not always have been humans who made them after all.

Researchers in Brazil witnessed something amazing – capuchin monkeys actually making stone flakes very similar to those made by early humans for cutting. So are these monkeys actually making tools? Well the answer is no. The capuchin monkeys were unintentionally making the stone flakes for an entirely different reason but scientists are still amazed at their ability to make them.

“It’s an incredibly interesting behavior,” says study lead author Tomos Proffitt, from the University of Oxford. “Another species is making sharp, conchoidally fractured flakes, an artifact that we only ever thought is unique to hominins.”

The stone flakes are being created by the monkeys as a result of a different kind of behavior – to break down the stone in order to ingest the minerals and lichen present.

Despite not intentionally making tools, it helps understand the early evolution of tool-making as “these findings challenge previous ideas about the minimum level of cognitive and morphological complexity required to produce numerous conchoidal flakes,” Proffitt stated.

Co-author, Michael Haslam, from the University of Oxford stated: “Our understanding of the new technologies adopted by our early ancestors helps shape our view of human evolution. The emergence of sharp-edged stone tools that were fashioned and hammered to create a cutting tool was a big part of that story. The fact that we have discovered monkeys can produce the same result does throw a bit of a spanner in the works in our thinking on evolutionary behaviour and how we attribute such artefacts. While humans are not unique in making this technology, the manner in which they used them is still very different to what the monkeys seem capable of.”

Details of the study were published in the journal Nature.