Tuesday, July 12, 2016

Monkey Tool Archaeology

Not only do contemporary capuchin monkeys use stone tools, but now a bit of non-human archaeology has shown that they have been doing it for at least 700 years:
An archaeological site in the Brazilian savanna has revealed the oldest record of non-human stone tool use found outside of Africa: centuries-old stone hammers and anvils wielded by hungry capuchin monkeys.

The rocks show that for at least 700 years, bearded capuchin monkeys (Sapajus libidinosus
) in Brazil’s Serra da Capivara National Park have smashed fresh cashews to peel off their caustic, unappetizing husks. The find confirms the behavior’s longtime importance to the area’s capuchins—which seem to have used the technique for a hundred generations—and adds vital nuance to the history of tool use in non-human primates. . . .

When Michael Haslam and his team of archaeologists and primatologists painstakingly dug up 377 square feet (35 square meters) of the savanna floor, they found 69 stone tools up to 2.7 feet (0.72 meters) below the surface.

The tools—worn-down hammers four times bigger than the average rock in the area, and pockmarked anvils four times bigger than the hammers—matched the form of modern capuchins’ tools. Chemical tests also revealed that the younger tools still bore cashew-husk residue, strongly indicative that they were once wielded by hungry capuchins.

What’s more, the team didn’t find any signs of indigenous or colonial human activity alongside the tools—a somewhat surprising absence, since Serra da Capivara is a World Heritage site and among the most important human archaeological sites in Brazil. Certainly, capuchins didn’t seem to pay Europeans any mind: some of the oldest capuchin tools dated back as far as 1266 A.D., more than 200 years before Columbus’s arrival in the Americas.
This creates new questions for the archaeology of humans, since it means that anywhere there are monkeys, simple stone tools are not enough to prove human presence. Some of those "famous archaeological sites" mentioned above are controversial because they date back to 60,000 years ago, but the artifacts are just broken quartzite cobbles that might have been left by monkeys rather than people.

On the other hand this research, along with studies of chimpanzees, answers one old questions about humanity. When did we start using stone tools? We always have, since our ancestors started well before we were human.

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