Scientists created a spear using tar they produced from a makeshift hearth to test whether Neanderthals might have used similar methods to obtain tar. Ochandoet al., Quaternary Science Reviews, 2024When fire was invented, it changed the course of human evolution. It provided warmth, enabled cooking and facilitated the creation of more advanced tools. For instance, one pivotal tool, the stone-tipped spear, might have been assembled using tar and other adhesives. While early tar production remains largely a mystery, scientists have now uncovered a 65,000-year-old hearth that appears to have functioned as a small-scale tar factory.In a new study published in Quaternary Science Reviews in November, scientists describe a 65,000-year-old hearth found in Gibraltar on the Iberian Peninsula. The fire pit was theoretically used to make tarand if that conclusion is proven true, it also represents the first evidence of the use of the plant rockrose, Cistus ladanifer, for obtaining tar.For this reason, it can be said that it was unexpected, says Juan Ochando, lead author of the study and a biologist at the University of Murcia in Spain, to Discover magazines Paul Smaglik.Scientists already knew that Neanderthals made adhesives using other materials like ocher and naturally sticky substances to haft stone tips onto wooden shafts to create weapons. The newly described hearth in Gibraltar represents a specialized burning structure for tar production, the researchers write in the study.Stone Age adhesives are an important and still much understudied aspect of early humans, says Patrick Schmidt, an archaeologist at the University of Tbingen in Germany who was not involved with the study, to Sciences Taylor Mitchell Brown.Still, Schmidt says that although the study points to wood burning in the hearth, more evidence is needed to conclude for certain that Neanderthals used the hearth to make tar. The Gorham's Cave Complex in Gibraltar has revealed several findings about Neanderthal history. Visit Gibraltar via Wikimedia Commons under CC BY 2.0The ancient hearth was uncovered in the Vanguard Cave, part of the Gorhams Cave Complex, a UNESCO World Heritage Site in Gibraltar. This area is renowned for its rich history of Neanderthal findings, including tools and cave art. Research in the Vanguard Cave began in 2012, and since then, scientists have revealed several new findings in its passageways and chambers.One such discovery was a cave chamber full of ancient hearths and stone tools dating to the time of Neanderthals, uncovered in 2021 by Clive Finlayson, an evolutionary biologist and director of the Gibraltar National Museum. He told the Guardians Sam Jones at the time that the caves have been giving us a great deal of information about the behavior of these people.That remains true today with the discovery of the prehistoric hearth, where researchers found charcoal and remnants of the rockrose plant. Chemical analysis of the hearths contents revealed burning residues and traces of wax from leaves, suggesting the controlled use of fireand possibly the production of tar. The team also found guano, or bat and bird poop, in the hearth. They suggest Neanderthals used guano with a mix of sand to cover the plant materials, allowing them to heat up and melt without fully catching fire. The researchers used the same materials and methods that would have been available to Neanderthals at the time to recreate the prehistoric hearth and produce tar. Ochandoet al., Quaternary Science Reviews, 2024To prove it is possible to produce a significant amount of tar from rockrose resin, Ochando and his team set out to make a similar hearth. They intended to do so with materials and techniques that wouldve been available to Neanderthals in the area at the time.First, they filled their replica hearth with rockrose leaves, then covered them with sand and soil. They built a small fire with grass and rockrose wood and let it burn for two hours. Afterward, the result was a mixture of rockrose leaves dripping with labdanum, a sticky resin, that the scientists used to haft arrowheads to wood in a type of makeshift spear.For Neanderthals, this effort might have been a cooperative process, as study co-authorFrancisco Jimnez-Espejo,a scientist at the Andalusian Earth Sciences Institute in Spain, tells Live Sciences Kiona Smith. On either side of the hearth, the researchers found a pair of straight furrows cut in the ground, where he suggests two Neanderthals might have dug into the hearth to remove the hot leaves from opposite sides. Separating the tar from the leaves is much harder when the leaves have cooled, so they had to work quickly, he adds.Although this production of tar will require further study, Ochando says the work aligns with the current suppositions about tar production. As he tells Science, Ochando hopes the findings may serve as a starting point for other researchers when identifying these structures in other archaeological sites.Get the latest stories in your inbox every weekday.Filed Under: Archaeology, Caves, Fire, Hominids, Innovations, Neanderthal, New Research, Technology, Tools, Weapons