Scientists are studying a group of long-tailed macaques in Thailand who have been observed making stone flakes, a behavior previously thought to only be exhibited by early humans. This discovery has prompted questions about the evolution of early humans and their use of tools.

The macaques were first observed using stone tools to crack open oyster shells in 2007. However, it wasn’t until recently that scientists noticed the monkeys were actually making the tools themselves. In a study published in the journal Nature, researchers documented the macaques using a “direct hard hammer technique,” similar to the one used by early humans.

While the discovery is exciting, it also raises questions about the timeline of when early humans developed their tool-making skills. The macaques are believed to have been using stone tools for 50 to 100 generations — a relatively short amount of time compared to the estimated 3.3 million years since the first stone tools were produced by early human species.

“This new finding begs the question of what makes humans unique and what makes us special,” said Lydia Luncz, a researcher at the University of Oxford and lead author of the study. “It also highlights the importance of not making assumptions about human uniqueness based on our lack of knowledge of other species.”

The discovery also has practical applications in the field of conservation. By studying the behavior of these macaques, scientists hope to gain a better understanding of how early human societies developed their tool-making skills and how this contributed to their survival.

“It’s one thing to say that early humans used tools, but to see another primate species doing almost the same thing, it sheds a different light on the evolution of the human brain,” said Michael Haslam, director of the Primate Archaeology project at the University of Oxford.

As researchers continue to study the macaques and their tool-making abilities, it is clear that this discovery has the potential to revolutionize the field of anthropology and bring new insight into the evolution of early humans.