The idea that Neanderthals were demonstrably clever because they used a difficult-to-make tar-based glue has hit a sticking point — the tar can be made simply as well.
It had long been thought that the tar, made from the bark of birch trees and used to manufacture tools, had to be produced in oxygen-free conditions.
Such environments preserve certain chemical components that may otherwise burn off and would require the bark to be burnt underground or in a ceramic container.
It had been argued that these approaches are complex and ‘cognitively demanding’ and evidence of Neanderthals’ capacity for advanced thought and planning.
However, experimental archaeologists have now shown that the glue can also be made by burning bark out in the open against the vertical side of a stone.
As the flames lick the stone, tar is deposited. Just three hours of burning was found to produce enough tar to glue a usable tool together.
The fact that a simpler way to make tar exists does not mean that Neanderthals were not smart, however — just that the tar alone is not proof of complex thought.
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The idea that Neanderthals, pictured, were demonstrably clever because they used a difficult-to-make tar-based glue has hit a sticking point — the tar can be made simply as well
Experimental archaeologist Patrick Schmidt of the University of Tübingen, Germany and colleagues tried instead to burn birch bark in the same kind of open air environment that the Neanderthals would have inhabited.
The researchers found that no tar was left behind when the burnt bark directly on top of flat river stones — but if they placed the rocks next to the fire, with flames licking the stone’s surface, a visible tar deposit quickly formed.
Within three hours, enough of the sticky tar had been formed that it could be scraped off and used for various processes, including the manufacture of simple tools.
‘Tar production can be an accidental, and indeed even a likely, outcome of everyday activities for any group building fires with birch,’ the researchers wrote.
The condensation technique is not a good indicator of complex, modern human-like cognition, they added, as it involves ‘a mere repetition of bringing two objects in close proximity and gathering of a resource.’
Such, they concluded, ‘is well within the cognitive power even of nonhuman great apes.’
The researchers found that no tar was left behind when the burnt bark directly on top of flat river stones — but if they placed the rocks next to the fire, with flames licking the stone’s surface, a visible tar deposit quickly formed
Within three hours, enough of the sticky tar had been formed that it could be scraped off and used — such as for the manufacture of simple tools. Pictured, a 0.62 gram piece of tar produced in a single three hour session which included bark collection
To demonstrate that their glue indeed worked, the researchers used the tar to attach a flint flake to a wooden tool handle — which they then used to both scrape wood and remove the flesh from a calf’s leg bone.
Despite the pressures placed on the glue by these activities, the flake remained attached to the handle.
Comparison of the researcher’s glue and tar made by the more complex, oxygen-free process revealed that the simpler approach actually produced a stronger glue.
Chemical analysis of their tar revealed that it was similar in makeup to samples archaeologist have found on tools dug up from Neanderthal sites.
To demonstrate that their glue indeed worked, the researchers used the tar to attach a flint flake to a wooden tool handle — which they then used to scrape wood, pictured
To demonstrate that their glue worked, the team used the tar to attach a flint flake to a wooden tool handle — which they then used to removed the flesh from a calf’s leg bone, pictured
The researchers suggested that the idea that Neanderthals used oxygen-free methods to create their primitive glue likely stemmed from the discovery of younger — Bronze Age — tar distillation apparatuses from Italy.
‘Our findings do not necessarily lead to the conclusion that Neanderthals were not able to conduct complex procedures, nor that they were not capable of abstract thinking or high planning depths,’ the researchers wrote.
There are many other forms of evidence that support Neanderthals’ capacity for complex thought — including their cave art and suspected burial rituals.
‘We merely note that, in archaeological science in general, arguing for abstract concepts like modernity or complex cognition in past populations should not rely solely on highly interpretative models.’
The full findings of the study were published in the journal Proceedings of the National Academy of Sciences.
WHO WERE THE NEANDERTHALS?
The Neanderthals were a close human ancestor that mysteriously died out around 50,000 years ago.
The species lived in Africa with early humans for hundreds of millennia before moving across to Europe around 500,000 years ago.
They were later joined by humans taking the same journey some time in the past 100,000 years.
The Neanderthals were a cousin species of humans but not a direct ancestor – the two species split from a common ancestor – that perished around 50,000 years ago. Pictured is a Neanderthal museum exhibit
These were the original ‘cavemen’, historically thought to be dim-witted and brutish compared to modern humans.
In recent years though, and especially over the last decade, it has become increasingly apparent we’ve been selling Neanderthals short.
A growing body of evidence points to a more sophisticated and multi-talented kind of ‘caveman’ than anyone thought possible.
It now seems likely that Neanderthals buried their dead with the concept of an afterlife in mind.
Additionally, their diets and behaviour were surprisingly flexible.
They used body art such as pigments and beads, and they were the very first artists, with Neanderthal cave art (and symbolism) in Spain apparently predating the earliest modern human art by some 20,000 years.
