Early humans' ability to shape stones into tools, such as sharp-edged flakes by striking two stones together to make them more useful for cutting, was a distinguishing feature of our ancestors' evolution. However, new findings from Max Planck Institute researchers have generated contentious conjecture.
A remarkable and contentious new study by researchers at the Max Planck Institute suggests that the evolution of human tool use among ancient man may have been less purposeful and more accidental.
Wild monkeys observed in the forests of Thailand were able to create stone artifacts “indistinguishable from what we see at the beginning of the [human] archeological record — what we see as the onset of being human,” said Lydia Luncz of the Max Planck Institute for Evolutionary Anthropology, a co-author on the study.
But the real issue is that, according to research by the Planck team published in Science Advances, the long-tailed macaques appear to have made their stone tools by mistake.
Primate species, such as the long-tailed macaques found in Southeast Asia, frequently use stones to crack oyster shells on the sand in order to get at the tender flesh inside.
The researchers emphasized that in order to do this, the beachcombing monkeys would select heavy, narrow stones, also known as "axe hammers" by anthropologists. The first-ever proof that these monkeys were using stone tools for food other than just cracking shells—nuts—astonished the researchers.
The researchers observed the animals scavenging for African oil palm nuts at an abandoned oil palm plantation in a Thai national park using set-up video traps. With carefully chosen "hammer" rocks in their hands, the monkeys there cracked open the nuts.
As an anvil, a smooth stone was employed. The primates occasionally failed to score, though. In such cases, the two stones colliding unintentionally would produce jagged stone fragments.
Anthropologists assert that this procedure was intentional in early humans. Knapping is the term archaeologists use to describe the process of breaking apart rocks to make improved tools. Strangely, these prehistoric tools are eerily identical to those "accidentally" made by macaques.