La Jornada: Study: Homo erectus used fire opportunistically and recurrently

Madrid. A study by the National Museum of Natural Sciences (MNCN-CSIC), in collaboration with the University of Toronto, reveals that populations of The man stood up who occupied the Wonderwerk cave in South Africa used fire opportunistically and recurrently earlier than previously thought.

Until now, the study of layer 10 dated the use of fire at the site to approximately one million years ago. Now, the new work published in the magazine PlosOne presents the analysis of layer 11, which reveals how our ancestors, although they did not know how to produce fire, introduced it into the cave during the Early Pleistocene, between 1.07 and 1.79 million years ago.

These results have been possible thanks to a new non-invasive methodology based on luminescence that identifies the effect of fire on the remains of micromammals found at Wonderwerk.

With this work it has been possible to demonstrate that the fire was intentionally introduced inside the cave, about 30 meters from the entrance, which rules out that the burned remains are the result of natural fires and confirms this as the record of fire associated with the genus. Homo oldest known.

According to taphonomic studies (a discipline that explains the fossilization processes of organic remains), the presence of raptors in the cave has been documented for almost 2 million years.

In fact, they still occupy the cave today. That is why the ground must have been covered with pellets (compact balls with the remains of undigested food) regurgitated by birds of prey.

The collection of remains of bones and hair from the pellets made it possible for The man stood up It would maintain the fire by burning the remains as a wool rug would, where the fire does not spread, but burns where it is left. “This is a very subtle fire that we have identified in the bones of small mammals,” explains MNCN researcher Yolanda Fernández-Jalvo.

At the levels analyzed, the team identified clear evidence of combustion in the remains of micromammals deposited by raptors, especially in the oldest stratum, where in certain areas 100 percent of the fossils analyzed showed unequivocal signs of having been exposed to high temperatures.

“This context, which eliminates the ambiguity that remains of bones that have served as food sometimes present, points to an opportunistic use of fire, probably brought from outside and kept inside the cave until it is extinguished.” explains Michael Chazan, researcher at the University of Toronto.

“The methodology we have developed allows us to distinguish burned fossils from those that have suffered chemical alterations during fossilization, such as fluoridation or manganese deposits, which can visually imitate the effects of fire. We have improved the resolution with which we can identify burned fossils in very ancient contexts,” says Fernández-Jalvo.

For her part, Marin-Monfort, first author of the article, emphasizes that “it is a fast, non-destructive technique that is easily applicable to large groups of remains, which makes this portable and low-cost luminescence protocol a tool that can be used directly in field excavations, in addition to offering the possibility of reviewing old sites.”

The use and subsequent control of fire is considered one of the most decisive innovations in human evolution since it provides light, heat and protection from predators, allowing new forms of social interaction and transformation of the environment.

No evidence has yet been found in Wonderwerk that hominins, that is, our ancestors with bipedal locomotion, knew how to produce fire. Nor has it been shown that they cooked food, a second innovation that enhances brain development in Homo.

Knowing how and when the use of fire began is essential to understand the biological and cultural changes that characterize the genus. Homo. “Our findings push back the chronology of fire associated with hominins and provide a solid methodological basis for future research,” concludes Liora K. Horwitz, co-director of the Wonderwerk project with M. Chazan.