Let’s be honest for a second here — we say humans ‘mastered’ fire, but most of us wouldn’t be able to light something up without some matches to save our lives.
It’s understandable, then, for researchers to assume that early humans likely harvested (instead of starting) fires. However, the ability to harness fire was a key developmental step for our species, enabling us to cook, protect ourselves from wildlife, or just by making the cave a more enjoyable place to hang around in. As such, archeologists are very keen (and eager to debate on) when exactly we learned to start fires.
New research from an international team now reports that Neanderthals, one of our ancient (and now extinct) relative species knew how to produce fire, overturning our previous assumptions.
Baby light my fire
“Fire was presumed to be the domain of Homo sapiens but now we know that other ancient humans like Neanderthals could create it,” says co-author Daniel Adler, associate professor in anthropology at the University of Connecticut (UConn). “So perhaps we are not so special after all.”
The team drew on hydrocarbon and chemical isotope analysis, archeological evidence of fire use, and models of the Earth’s climate tens of thousands of years ago to show that our ancient cousins did indeed know how to light a fire. The study focused on the Lusakert Cave 1 in the Armenian Highlands.
The team analyzed sediment samples to determine the level of polycyclic aromatic hydrocarbons (PAHs) — compounds that are released by burning organic materials. Light PAHs disperse widely, the team explains, and are indicative of wildfires. Heavy PAHs, on the other hand, spread narrowly around a source of fire.
“Looking at the markers for fires that are locally made, we start to see other human activity correlating with more evidence of locally-made fire,” says lead author Alex Brittingham, a UConn doctoral student in anthropology.
Higher levels of heavy PAHs at the site (which indicate regular fire use) correlate with evidence of increased human occupation (such as dumps of animal bones from meals) and of tool making, the team explains.
In order to rule out the possibility that these fires started naturally (for example, following lightning strikes), the team analyzed hydrogen and carbon isotope ratios in plant waxes preserved in sediment from those ancient days. This step is useful for recreating the kind of climate the plants grew in, the team reports. All in all, they didn’t find any link between the paleoclimatic conditions at the time and the chemical evidence left over by the fires. The inhabitants were not living in drier, wildfire-prone conditions while they were utilizing fires within the cave.
“In order to routinely access naturally caused fires, there would need to have been conditions that would produce lighting strikes at a relative frequency that could have ignited wildfires,” says Michael Hren, study author and associate professor of geosciences.
In fact, the team reports that there were fewer wildfires going on in the area while humans inhabited the cave (light PAH frequency was low while heavy PAH frequency in the cave was high). This finding suggests that the Neanderthals acted as a kind of fire control in the area they inhabited, intentionally or not. It also shows they were able to control (i.e. start) fire without having to rely on natural wildfires.
The team now plans to expand their research to other caves occupied by early humans, to determine whether different groups learned to control fire independently of people in other geographic areas. In other words, was it something that only certain groups figured out, or more wide-spread knowledge?
The paper “Geochemical Evidence for the Control of Fire by Middle Palaeolithic Hominins” has been published in the journal Scientific Reports.
