Human history is intimately linked to the use and control of fire. However, determining when our relationship with fire began and how it subsequently evolved has been notoriously difficult.
This is partly due to the incomplete nature of the archaeological record, and also because the use of fire was ephemeral, making burnt remains difficult to detect.
But our team has found evidence of the controlled use of fire by direct human ancestors – or hominids – at a site in Spain dating back 250,000 years ago.
This pushes back the earliest evidence of fire control in Europe by 50,000 years. The findings were published in Nature Science Reports. It’s really special to find the remains of human ancestors and fire in the same place.
There is much older evidence of hominins exploiting fire, but it could have taken the form of hominins taking advantage of the burning embers of a natural forest fire to cook their food.
The controlled use of fire is where humans intentionally start it and then manage, for example, its extent or temperature. This is what we have proof of on the site in Spain.
Much older evidence from outside of Europe, which may be from humans using natural fires, comes from Swartkrans Cave in South Africawhere hominin remains were found along with hundreds of burnt animal bones dating to between 1 and 1.5 million years ago.
Burnt animal bone fragments have also been identified at the 1.5 million year old site known as FxJj 20AB in Koobi Fora, Kenya.
Yet finding hominid artifacts and burnt bones at the same site does not by itself indicate that they coincided in time, let alone that humans controlled the fire. The path to its controlled use was probably gradual.
Fast forward nearly a million years to the earliest known clear evidence of a man-made fire: an outdoor site called Gesher Benot Ya’aqov in Israel, dated to around 790,000 years old. Evidence found at this location includes charred plants and burnt stone tools lying next to each other.
Other sites in Israel, such as the Quesem Cave, with finds dating from between 420,000 and 200,000 years ago and Tabun Cave, where archaeological finds are about 340,000 years oldshow similar evidence of fire.
Although early evidence such as this suggests fire control, a direct link between resources such as firewood, activities such as fire preparation, and intent – arguably a prerequisite for fire control fires – can be difficult to establish.
In Europe, it is generally accepted that fire was commonly exploited by hominins at least 350,000 years ago, with some fire control suggestions being related to the expansion of a particular stone tool technology known as the Acheulean.
Indeed, there is a simultaneous increase in apparent prehistoric “chimneys”, or hearths, and burnt Acheulean artifacts, such as flint hand axes and a sedimentary rock called chert, at many European sites dated between 450,000 and 250,000. Many of these also contain charred plant matter and bones.
Yet there are reasons to believe that these associations are of natural origin – for example, forest fires or lightning strikes.
Prior to the new evidence, the oldest clear evidence of firefighting in Europe came from Menez-Dregan in France and Bolomor Cave in Spain, both dated to around 200,000 years ago.
Abrigo de la Quebrada in Spain, dated to around 100,000 years ago, is another ancient site with clear evidence of the use of domestic fire.
New evidence from the site of Valdocarros II in Spain, dated to around 250,000 years ago, serves as a new benchmark for understanding our ancient relationship with fire.
Lipid biomarkers are the remnants of molecules from specific sources, such as particular types of wood, and left over from processes such as fire.
Recently published data on lipid biomarkers from various archaeological sites reveals details about the unique resources – for example, types of wood – used to create isolated campfires associated with Acheulean artifacts.
Lipid biomarker evidence from Valdocarros shows diagnostic signatures indicating that decaying pine was used as fuel.
Curiously, records of pollen and the relationship between water and climate in the surrounding region suggest that the decaying pine would have been a scarce resource.
Corroborating evidence comes in the form of molecules called polyaromatic hydrocarbons, or PAHs, which are products of incomplete combustion. Analysis of these reveals that decaying pine at Valdocarros II was burned at low temperatures of around 350°C for relatively short periods of time.
Fires that are too hot tend to char and burn food on the outside before the inside of the item has reached a useful temperature. Lower temperatures are needed to break down biological tissues so that they are easier to digest – one of the main reasons for cooking food.
Conversely, low-temperature fires are unlikely to have been used solely for heat, given the much more common wood burns at higher temperatures. Another advantage of using rotting pine is that it is easy to ignite.
Thus, the fires of Valdocarros II seem to have been used for activities such as cooking. The intriguing record of the use of fire at this Spanish site is beginning to emerge after combining all the available evidence.
For example, there is a rich fossil record of mammals at Valdocarros II which includes many slaughtered animals red deer (Cervus elaphus) and the wild ancestors of domestic cattle, known as aurochs (Bos primigenius). The aurochs could each weigh up to 1,500 kg or more.
Thus, the hominids present on this site have all the necessary prerequisites for fire control: the use of specific resources such as decaying pine wood; specific activities, such as low-temperature fires used for cooking; and intent, which may be implied by the need to transport large carcasses to a single location where fire was used.
By any standard, the hominids of Valdocarros II controlled the fire. The site is not the oldest, nor the first case of fire under control. Rather, it is an important benchmark in the course of human evolution, as it sets a clear time limit to the emergence of a defining human characteristic.
The work of Valdocarros II also creates the opportunity for a broader discussion of how to establish intent and foresight from archaeological evidence, as well as the larger body of human evolution and culture. prehistory.
Clayton MagillAssistant Professor, School of Energy, Geosciences, Infrastructure and Society, The Lyell Centre, Heriot Watt University
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