The analysis of one of the oldest paintings in the world confirms its human origins

Cueva de Ardales (Malaga).
Cueva de Ardales (Malaga).

One of the main challenges in archaeology is to discover the time when the symbols appeared and the implications of their use in human behaviour. The oldest paintings found to date are those from the three Spanish caves in Caceres, Cantabria and Malaga, which would be about 65,000 years old. Their dating brought an intense debate in the scientific community, because it suggests that the paintings would have been made by Neandertals. Now, an international team led by researchers of the University of Barcelona proves that, contrary to what some authors think about the findings, the red marks on a series of stalagmites in Cueva de Ardales (Malaga), result, without any doubt, from human activity. According to this study, the Neandertals would have accessed the cave in several occasions to mark symbolically and repeatedly the stalagmitic formation located in the middle of a big room. The study highlights, in addition, that the used ochre for these paintings would have been taken outside the cave. The results of this study are published in the prestigious journal Proceedings of the National Academy of Sciences.

Despite the efforts made by many researchers to document and interpret cave art, there are many questions left on the origins, chronology, technology, function and meaning of this type of art. The studies carried out over the last years have mainly focused on the dating of the oldest paintings with the uranium-thorium dating method. This technique, applied to calcite concretions in stratigraphic association with the paintings, shows that these types of artistic manifestations are older than what it was initially thought. In analysed paintings from Borneo and Sulawesi (Indonesia), for instance, researchers have obtained minimum ages of 39,900 and 43,900 years old respectively. Another example is the cave El Castillo (Cantabria) where researchers obtained the minimum age of 40,800 years old for a red disc. The oldest chronologies, up to 64,8000 years old, correspond to a hand in negative (Maltravieso, Caceres), a set of lines forming a symbol similar to a ladder (La Pasiega, Cantabria) and a set of colourful stalagmites (Ardales, Malaga).

These last chronologies have been the object of controversy among the scientific community. They would point out that the artistic manifestations had appeared at least 20,000 years before the arrival of modern humans to the European continent, which would point out to a Neanderthal authorship. In order to provide an alternative, the sceptic ones doubt the red marks of the surface of the stalagmitic rock in Cueva de Ardales, for instance, are a result from human activity. However, the study carried out by an international team led by UB researchers goes against this hypothesis and it allows, at the same time, to know more about the behaviour of the cave visitors who made these red marks.

Studies in Cueva de Ardales

The cave Cueva de Ardales, also known as Cueva de Doña Trinidad, is located in the eponymous town, in the provincial area of Malaga, in the south of Spain. The cave was discovered in 1821 after an earthquake opened an entrance that had been previously closed. The first to study the art of the cave was Henri Breuil in early 20th century, although it did not udergo excavations until later. Currently, Cueva de Ardales is one of the caves with the most important Palaeolithic parietal art in the south of Europe: more than a thousand graphic representations, abstract and figurative, have been counted. Among the artefacts found inside the cave are processing tools for colorants and pigment fragments, some of which would have been taken from levels of the Middle and Upper Palaeolithic. As mentioned above, this site has been the focus of attention recently because it contains some of the oldest paintings in the world. To date, however, the pigments that make up the cave paintings had not been studied.

Study of the reddish residues in the laboratory

With the analysis of small quantities of the reddish residue taken in the surface of the stalagmites, the researchers reached the conclusion that it is an intentionally applied ochre-based pigment. "Both the location and distribution of the marks as well as the size and morphology of crystals that build up these red residues rule out the option of being natural-origin deposits, whether they derive from the action of microorganisms or geological processes such as river flows, water percolation or the weathering of walls", notes Àfrica Pitarch, principal researcher of the project. The comparison of these residues to samples from several deposits of iron compounds in the inside of the cave suggests, in addition, that the used pigment for painting these paintings is likely to come from an outcrop outside the cave. "The ferruginous deposits of the cave present textural and compositional features that are different from those observed in archaeological samples", adds the researcher. "This would involve that the authors of these red marks had to look for, select, collect and bring the coloured matter they afterwards would use in the cave, that is, there was a certain level of organization", concludes Àfrica Pitarch.

The underground world and symbolic systems of the Neanderthals

The researchers have also observed that variations in composition between the painting samples correspond to the differences in chronology of the stalagmitic layers that cover it, and sometimes, can be thousands of years old. This fact would indicate that several generations of Neanderthals would have visited the cave and would have repeatedly marked with red ochre the great stalagmite dome. Based on these findings, the researchers think that painting stalagmites cannot be considered "art" in the strict sense of the term but it would be the result of graphic behaviours with the goal of perpetuating the symbolic meaning of a place. The type of markings may represent the beginning of a long process in which the new needs linked to social complexity would have triggered the emergence of new symbolic traditions linked to more varied and innovative technical practices.

"Data from Cueva de Ardales and other Iberian caves with parietal art made more than 65,000 years ago indicate that the underground world played a key role in the symbolic systems of Neanderthal communities", notes João Zilhão, supervisor of the project. "The action of repeatedly marking with red pigment speleothems as imposing as the dome of Ardales suggests that their authors wanted to highlight and perpetuate the importance of this location through narratives passed down between generations", adds the expert. "At the same time, it would strengthen the cohesion between the members of the group and their link with the territory", he concludes.

"The research line led by Dr. Pitarch and Dr. Zilhão, of great international impact, opens new perspectives in the field of the symbolic attitudes of the Neanderthals; it is something to be proud of at SERP, our research group of the University, to lead careers like this, at the at the forefront of prehistoric science", says Josep Maria Fullola, co-author of the study and director of the SERP-UB research group.

This study, led by Àfrica Pitarch Martí and supervised by João Zilhão, has been funded by the Beatriu de Pinós - AGAUR program (project 2017 BP 00046) and has been carried out wihin the structure of the Prehistoric Studies and Research Seminar (SERP), in collaboration with researchers from national and International universities and institutions.

Reference arctile:

Pitarch Martí, A., Zilhão, J., d’Errico, F., Cantalejo-Duarte, P., Domínguez-Bella, S., Fullola, J.M., Gerd C. Weniger, G.C., Ramos-Muñoz, J. "The symbolic role of the underground world among Middle Palaeolithic Neanderthals". Proceedings of the National Academy of Sciences, August 2021. DOI:­2021495118