In 1973, a French-Brazilian team pushed their excavations into a rock shelterRock shelterA shallow cavity at the foot of a cliff or under a rocky overhang, offering natural shelter; a favoured site of prehistoric habitation and rock art.→ in the Serra da Capivara National Park, in Brazil's northeastern Piauí state. What they found would ignite one of the fiercest debates in world prehistoryPrehistoryThe span of human history before the invention of writing, from the Palaeolithic to the Metal Ages, known mainly through material remains.→: charcoal dated between 32,000 and 48,000 years before present, and quartzite fragments that looked disturbingly like knapped tools. If these dates are correct, humans were living in South America long before the ClovisClovisA Palaeoindian culture of North America (c. 13,000 years ago), recognizable by its fluted stone points; long believed the oldest on the continent, no longer so.→ people, long considered the "first Americans" who crossed the Bering land bridgeBering land bridgeThe strip of land (Beringia) linking Asia to America during the last Ice Age, the entry route of the first Americans.→ some 13,000 years ago.
\n\nSince then, Pedra Furada has divided archaeologists worldwide. On one side, Niede Guidon and her international team defending dates going back as far as 60,000 years. On the other, North American researchers such as David Meltzer, James Adovasio and Tom Dillehay, who dismiss the evidence as the product of natural processes. The debate, far from settled, touches on one of prehistory's most fundamental questions: when and how did humanity populate the last great habitable continent on Earth?
\n\nA rock shelter in a landscape of stone
\n\nPedra Furada means "pierced rock" in Portuguese, referring to a natural quartzite arch that towers over the Brazilian caatinga scrubland. The site lies within the Serra da Capivara National Park, a UNESCO World Heritage Site since 1991, which contains more than 800 archaeological sites spread across 100,000 hectares. Engraved walls, shelters adorned with vivid paintings depicting humans, animals and hunting scenes: Serra da Capivara is one of the largest rock artRock artThe whole body of graphic representations (painted or engraved) made on rock walls, slabs or blocks.→ complexes in the Americas.
\n\nBrazilian archaeologist Niede Guidon, trained in France and affiliated with the School for Advanced Studies in the Social Sciences (EHESS), has been the driving force behind the excavations since the 1970s. She assembled a multidisciplinary team under the banner of the Fundacao Museu do Homem Americano (FUMDHAM), the foundation she created to protect and study the site.
\n\nThe main Pedra Furada shelter offers exceptional preservation conditions. The overhanging rock face protects deposits from weather, allowing charcoal, bones and lithic tools to survive across dozens of successive stratigraphic layers. Guidon identified 15 distinct levels corresponding to three major cultural phases: the Pedra Furada phase, the oldest and most contested; the Serra Talhada phase (12,000 to 7,000 BP), with well-attested quartzite tools; and the Agreste phase, contemporary with rock paintings dated 11,000 to 5,000 years old.
\n\nDates that push every limit
\n\nThe first radiocarbon analyses, conducted in 1985 at the CNRS in Gif-sur-Yvette, France, produced spectacular results: charcoal from the deepest layers yielded ages between 32,000 and 48,000 BP. Publication in 1986 in the journal Nature[1] by Guidon and Delibrias sent shockwaves through the scientific community.
\n\nA newer protocol, ABOx-SC, applied to seven hearthhearthA combustion structure set on the ground, evidence of the mastery of fire and a marker of how a prehistoric dwelling was organised.→ samples using accelerator mass spectrometryMass spectrometryA technique that measures the mass of molecular fragments very precisely in order to reconstruct their composition, here the sequence of proteins.→ at the Australian National University, pushed dates further back: 55,000 to 60,000 BP for the oldest levels. In 2013, the nearby site of Toca da Tira Peia yielded remains dated to 22,000 years using optically stimulated luminescence (OSL)Luminescence (OSL)Optically stimulated luminescence dating: measures the last exposure of sediment grains to light.→, lending indirect support to Guidon's claims.[2]
\n\nIf these figures are accepted, they imply that anatomically modern humans crossed either the Atlantic or Pacific Ocean long before the Last Glacial MaximumLast Glacial MaximumThe peak of the last glaciation (c. 26,000 to 19,000 years ago), with ice sheets at their greatest extent; it pushed populations towards southern refuges.→. Guidon herself has floated, as a hypothesis, a trans-Atlantic migration from AfricaAfricaThe cradle of humankind: the continent where the first hominins appeared, then Homo sapiens around 300,000 years ago, before the expansion to the rest of the world.→ -- which only stiffened her critics' resolve.
\n\nThe case for the sceptics: natural fires and monkey tools
\n\nThe most classic objection, raised in 1994 by Tom Dillehay, concerns the origin of the charcoal. He and colleagues Meltzer and Adovasio argued that natural vegetation fires could have deposited charcoal in the shelter without any human intervention. The caatinga is prone to intense droughts and spontaneous fires; wind-borne carbonised particles could easily have been carried into rock crevices over tens of millennia.
\n\nThe second objection concerns the tools themselves. Critics see the quartzite flakes as geofacts -- fragments produced naturally by rocks falling from the cliff above the site. James Adovasio was blunt: "The Pedra Furada stuff is not even up to capuchin standards." This quip references a surprising discovery: black-striped capuchin monkeys (Sapajus libidinosus) in Serra da Capivara National Park have been observed smashing pebbles against rocks to extract quartz dust. The flakes they produce are morphologically similar to the oldest "tools" at Pedra Furada.[3]
\n\nGuidon's counter-arguments
\n\nGuidon has never yielded under pressure. Her main counter-argument against the natural fire thesis is geographical: the charcoal is concentrated in circular structures bounded by stones -- exactly what one would expect of intentional hearths. "The charcoal is not from a natural fire. It is only found inside the sites. You don't get natural fires inside the shelters," she told The Guardian.
\n\nFrench lithic technologist Eric Boeda analysed the Pedra Furada phase pieces and concluded they are of human origin: some display intentional retouch impossible to replicate by simple rockfall. Jacques Pelegrin of the CNRS judges the natural process explanation "very unlikely" given the continuous human occupation proven in the site's upper levels.
\n\nPedra Furada and the peopling of the AmericasPeopling of the AmericasThe migrations that led Homo sapiens to occupy the American continent, from Beringia; its date and routes remain debated.→
\n\nThe Pedra Furada controversy cannot be separated from the great debate on the peopling of the Americas. For decades, the "Clovis first" model dominated: the first Americans were carriers of Clovis culture, dated 13,000 to 11,500 years ago. This model has been progressively dismantled. Monte Verde in Chile provided solid evidence of occupation at 14,800 BP. Meadowcroft Rockshelter in Pennsylvania (16,000 BP), the Topper site in South Carolina and Buttermilk Creek in Texas have all reinforced the case for pre-ClovisPre-ClovisA set of American sites older than Clovis (Monte Verde, Cooper's Ferry, etc.) that overturned the 'Clovis first' model.→ presence. Human footprints at White Sands, New Mexico, dated to 23,000 years, caused a sensation in 2021.
\n\nIn this context, Pedra Furada represents the most radical hypothesis: not a few thousand years before Clovis, but tens of thousands. Current genetic data, tracing the separation of Amerindian populations from Asian populations to roughly 15,000-25,000 years ago, make a 60,000-year presence extremely difficult to reconcile with the molecular record.
\n\nA debate far from over
\n\nIn 2026, no consensus is in sight. Most prehistory textbooks mention Pedra Furada as a controversial site whose most extreme claims are not accepted by the majority of specialists. But excavations continue, and each new analysis brings its load of ambiguous results. Serra da Capivara remains one of the most extraordinary prehistoric sites in the Americas. Whether its oldest layers were frequented by humans 48,000 years ago or by improvising capuchins, the paintings adorning its walls -- 11,000 years old -- remain a fascinating testament to the lives of the first known inhabitants of the New World.
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