Aug. 2 (UPI) -- Neanderthals painted art in Ardales cave in Andalusia, Spain, in prehistoric times -- debunking an alternative theory that it happened naturally -- researchers said Monday in a study published in PNAS.
A team of researchers, including some from the University of Barcelona and Ardales Cave and Prehistory Center, confirmed Neanderthals painted the cave by debunking an alternative theory for red stains on flowstones there.
The coloring predates the appearance of modern humans on the European continent by more than 20,000 years.
"Cuevas de Ardales in Malaga [Andalusia], Spain, is one of the richest and best-preserved Paleolithic painted caves of southwestern Europe, containing over a thousand graphic representations," researchers wrote in the study.
In particular, the research team examined the flowstone formation in a panel of the "Sala de Las Estrellas" part of the cave, which has large columns and evidence of prehistoric burials older than the Copper Age, according to PRAT-CARP.
The theory, that it was a natural coating of iron oxide deposited by flowing water, was debunked by comparing samples of red residues collected from the flowstone surface to other iron oxide rich deposits in the cave.
And they found that instead the Neanderthals had intentionally applied the red pigment.
"The conspicuously different texture and composition of the geological samples indicates that the pigments used in the paintings do not come from the outcrops of colorant material known in the cave," researchers wrote.
"We confirm that the paintings are not the result of natural processes," they wrote
The researchers added that the findings suggest that the "artistic activity" was "recurrent," indicating Neanderthals may have returned to the cave to symbolically mark the site for generations.