Were Europe's first artists Neandertals? An international team of archaeologists says it's a strong possibility. Improved dating techniques have revealed that the practice of cave painting began at least 40,800 years ago, around the same time that modern humans arrived in Europe.
But the paintings — which, at 40,800 years old, are easily the most ancient reliably dated cave art on Earth — could also be much, much older. If that's the case, say the researchers, it's likely that Neandertals, not Homo sapiens, are responsible for this prehistoric art work.
Cave art is one of the most important reference points archaeologists have in their efforts to reconstruct the emergence and evolution of culture throughout human history. But for as often as cave art appears in the archaeological record, it is notoriously difficult to date directly. Radiocarbon dating, for example — one of the most commonly used techniques in an archaeologist's tool set — is often unreliable when it comes to estimating the age cave art. Consequently, it's proven difficult to establish a reliable timeline of its history.
"We know very little about the chronology of European cave art," explains paleolithic archaeologist Joao Zilhao, coauthor of the study describing the cave paintings, appearing in this week's issue of Science. "We don't know if it arrived with the first modern humans… if it predated the arrival of modern humans, or [if it] arose 5,000 or 10,000 years after modern humans had already arrived in Europe."
In an effort to better establish what that chronology might look like, Zilhao joined forces with University of Bristol archaeologist Alastair Pike (pictured here), an expert in a technique called uranium-thorium (U-Th) dating. By putting a creative spin on this dating method, Pike was able to determine the minimum age of dozens of works of art in 11 Spanish caves — not by dating the works themselves, but by dating mineral deposits known as speleothems located directly adjacent to the paintings.
You've probably seen or heard of speleothems before, if not by that name. Some of the most widely recognized examples of these mineral formations are stalagmites and stalactites — solid mineral-spires, formed over the course of thousands of years, that project tooth-like from the floors and ceilings of damp cave systems.
But speleothems can take a variety of other forms as well, including thin, sheet-like formations known as "flowstone." Occasionally, flowstone will form over walls covered in paleolithic cave paintings. When it does, it becomes a time capsule. Logic dictates that anything encased in flowstone is certainly older than the flowstone itself, so by comparing the ratio of uranium and thorium atoms in the minerals deposited nearest the cave wall, archaeologists can acquire a reliable lower limit on the age of the art that lies just beneath.
Pike and Zilhao dated 50 works of cave art using this U-Th method, but three findings in particular really stood out. The researchers describe their findings in the latest issue of Science:
The results demonstrate that the tradition of decorating caves extends back at least to the Early Aurignacian period, with minimum ages of 40.8 thousand years for a red disk, 37.3 thousand years for a hand stencil [pictured up top], and 35.6 thousand years for a claviform-like symbol [pictured here].
If the earliest cave paintings appeared in the region shortly before 40.8 ka [40.8 thousand years ago], this would… support the notion that cave art coincided with [the arrival of modern humans] in western Europe ~41.5 ka, and that the exploration and decorating of caves was part of their cultural package. However, because the 40.8-ky date for the disk is a minimum age, it cannot be ruled out that the earliest paintings were symbolic expressions of the Neandertals, which were present [that region of] Spain until at least 42 ka.
When asked how confident they were that the cave art was, in fact, the work of Neandertals, the researchers stuck to the presented facts, saying that it is impossible to say at this point. That's not to say they don't have strong opinions:
"In probabilistic terms, I would say there is a strong chance that these results imply Neandertal authorship. But I will not say we have proven it because we haven't and it cannot be proven at this time. It's just, you know, my gut feeling if you want.
"What we have to do now is go back, sample more and find out whether we can indeed get dates older than 42, 43, 44,000 [years]."
Pike echoed his colleague's sentiments:
"Simply go back and date more of these samples," he explained, noting that investigations similar to this one are in the pipeline, "and find something that predates modern humans in Europe."
The researchers' findings are described in this week's issue of Science.