Small bones burned in a cave in South Africa point to a much older relationship between humans and fire than previously assumed.
The first humans to use fire probably They didn’t light it themselves. It is possible that they limited themselves to using it in their environment, probably after lightning or seasonal fires.
In a South African cave, a team of researchers has now found evidence that primitive human ancestors, perhaps The man stood up, carried fire to a shelter more than a million years ago — possibly 1.79 million years.
The evidence was found in the gruta de Miraclea vast tunnel in the Kalahari Desert that preserves almost two million years of occupation by ancestors of the genus Homo. Investigators had already identified signs of fire at the site dated around a million years.
The new, recently published magazine PLOS Onedates burned fossilized bones found in older layers of the cave, which could make go back almost 800 thousand years to the first reliable proof the use of fire by humans.
Fire is one of the technologies that made humans what they are. It brought light after sunset, warmth in cold environments, and protection from predators. It’s the most fundamental technology of any primitive civilization.
Much later, cooking would make food softersafer and richer in energy, with major consequences for the development of the human brain.
Mass origin of the use of fire has always been difficult to determine. The ancient fires are not preserved so clearly like an arrow with a stone tip. Ash and coal are organic materials that degrade easily.
In very specific conditionsHowever, traces of fire can last a very long time. AND the caves, it turns out, are excellent for thatnote or .
In the Wonderwerk cave, the burned bones were found about 30 meters from the entrance. Natural fires in the savannah would hardly have reached this far inland. The deposits also appear to have formed where archaeologists found them, and not been dragged there later.
“Evidence of fire in such ancient sites is often subtle and difficult to detect,” he says. Liora Kolska Horwitzresearcher at the University of Haifa, in Israel, and co-author of the study.
“Our study provides new tools to identify traces of ancient combustion and reveals that fire was repeatedly present in the deep interior of Wonderwerk Cave,” adds the researcher.
The oldest layer, designated Stratum 11belongs to early Acheuleanthe lithic culture known for its bifaces. In Wonderwerk, this layer marks the transition from olduvaense tools simpler for rudimentary bifaces, placing the use of fire close to a decisive moment in technological evolution.
The bones that betrayed the fire
Many of these charred remains came from owl egagropylae. The owls that took shelter in the cave swallowed small mammals and, later, regurgitated balls of bones, fur and other materials. Over time, these egagropylae will have formed dense patches on the cave floor.
If early humans carried fire into the cave, these regurgitated carpets of bones, fur and feathers could have acted as bait. When they burned, the small bones inside were also singed.
To test this hypothesis, the researchers used a new technique based on luminescence: They shined blue light on light-colored fossilized bones and observed them through a filter. The burnt bones gave off a red glow; the unburnt bones did not shine.
The team also turned to infrared spectroscopya more consolidated method that detects changes in bone minerals caused by heat. The two methods showed very consistent results. In Stratum 11, all 32 white and gray bones analyzed showed signs of combustion in both tests.
The team also analyzed bones from a more recent layer of Wonderwerk, from a Bronze Age site in Spain, and from experimentally burned modern bones. These comparisons helped demonstrate that brightness was a sign of fire, not just an effect of fossilization.
O combustion pattern also offered some clues. In Stratum 11, the burned bones were concentrated in distinct areas, rather than being evenly distributed throughout the excavation.
Two spots, separated by about five meters, showed signs of particularly intense combustionwhich points to repeated or localized fire episodes, rather than a single isolated event.
There are no relevant signs of food preparation nor established bonfires. Therefore, there is no reason to believe that the charred remains are the result of controlled fire the way humans would later do it.
The researchers consider that the most likely explanation is the opportunistic use of the fire. These hominins may have lived in a landscape where fire was common, watched how it spread, learned when it was useful, and started taking it to places it wouldn’t go naturally.
African savannas are long shaped by seasonal fires. For early humans, fire was a dangerous but familiar ecological force. Learning to explore it will have represented an important behavioral step.
“These discoveries show that early humans were not mere passive observers of natural fires,” explained Kolska Horwitz. “They were actively interact with fire and integrate it into their lives”.
