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Scientists find tools made by monkeys 3,000 years ago in Piauí – Bicharada

Photo: Reproduction Facebook Zoobotanical State Park

A community of monkey-natives in Piaui has used tools to break nuts and seeds for at least 3,000 years and has adapted its technique to different foods over time. The discovery helps to understand how intelligence similar to that of human ancestors evolved independently in prehistoric Brazil.

The conclusion came from an archaeological excavation at the Pedra Furada National Park in São Raimundo Nonato (PI), the results of which were published on Monday in the journal Nature Ecology and Evolution.

The authors, an interdisciplinary group that brought together biologists, psychologists and archaeologists, describe how monkeys have been learning from each other how to use rocks to process food.

The technique in question requires two stones, one to support the food being processed – the "anvil" – and another to strike it – the "hammer". Scientists who have been studying the region for more than two decades already knew that the monkey-nails that live there use stones of different sizes depending on the food being processed.

The region's current menu includes foods such as cashew nuts, maniocoba seeds, chickpeas and jatobá. While cashew nuts are easier to open with small stones, other foods usually require larger stones.

In analyzing the archaeological records left by monkeys over 450 generations, scientists saw that 3 millennia ago, small stones were preferred by apes. About 2,500 years ago, however, the animals began to use larger stones, and recently, about 100 years ago, they used the smaller stones again.

Photo: Reproduction Facebook Zoobotanical State Park

This variation, which indicates a possible need for adaptation to the environment and the type of food most abundant, is typical of the archeology of human tools.

"This is the first time that we have been able to identify this in a non-human archaeological site", says Tiago Falótico, a USP primatologist (University of São Paulo) and lead author of the study. "There are sites with chimpanzee tools dating back 4,000 years in Africa, but in that case 4,000 years are doing the same thing."

To ensure that the stones found in the excavation in Serra da Capivara the archaeologists made sure that that area had not been inhabited by humans before – they leave signs like ceramic shards and remains of fire. Discarded this hypothesis, the archaeological record could only be of the apes. Stones used by humans, moreover, are usually much larger than the pebbles up to 3 centimeters used by monkeys.

The case of the monkey-nails has aroused so much interest among scientists studying human evolution that archaeologists with experience working in East Africa – the "cradle of humanity" – are now going to Piaui to study New World primates.

This is the case of Tomos Proffitt of University College London and Richard Staff of the Center for Environmental Research of Scottish Universities who sign the new study together with Falótico. The group also includes a psychologist, Eduardo Ottoni, from USP, a pioneer in the study of monkey-nail intelligence.

Photo: Reproduction Facebook Zoobotanical State Park

One of the facts that most intrigued researchers dedicated to this issue is that these small South American primates have an evolutionary distance of about 40 million years for the other great chimpanzee monkeys, orangutans and gorillas. It is unlikely that the common ancestor between monkey-nails and the great apes (which is the same ancestor as humans have in common with the monkey-monkeys) has developed the ability to use tools for so long.

The monkey-nails, in addition to using stones to strike nuts, use rods as tools to harvest bee honey or to uncork lizards who want to eat. Because they are perishable, wands do not survive in the archaeological record, but there is nothing to indicate that they could not have been used during all this time.

Photo: Reproduction Facebook Zoobotanical State Park

The sophistication with which naive monkeys use tools today is a striking example of how the abstract intelligence required for it and the capacity for cultural transmission can evolve independently. Researchers are already able to see points in common with the situation in which human ancestors evolved in eastern Africa.

"The only genre of New World primates that use tools is that of the monkey-nail, and it can be studied as a more independent model for the emergence of tools and traditions," explains Falótico, drawing a parallel with the monkey-nail and human ancestral primates. "These groups that use tools are more 'terrestrial', that is, they use a lot of soil space, inhabit drier areas with savanna characteristics, and have adequate stones available to make these tools."

Scientists now intend to deepen the excavations in Serra da Capivara and study the ancient ecological changes of the region to better understand how these small noted monkeys related to the environment.

Source: FolhaPress

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