Stone surfaces may preserve memories that archaeology once missed.
Cáceres, June 2026
Scientists have recovered ancient human DNA from cave walls in Spain and Portugal, demonstrating that rocky surfaces can preserve traces of human presence for at least 2,000 years. The discovery introduces a new source of genetic evidence for archaeologists attempting to reconstruct how ancient populations entered, used and interacted with underground spaces. Until now, most research in this field depended on bones, teeth, sediments and artefacts recovered from cave floors. The walls themselves may now be understood as biological records capable of retaining information across generations.
The international investigation was coordinated from Cáceres and involved specialists from Spain, Portugal, Germany, the United Kingdom and China. Researchers examined samples associated with 24 rock art panels located in 11 caves across the Iberian Peninsula. Their findings were published in the scientific journal Nature Communications. The project developed from earlier studies of prehistoric art at Maltravieso Cave in Extremadura, where some of Europe’s oldest known painted motifs have been documented.
The study sought to determine whether human genetic material could survive directly on surfaces containing or surrounding prehistoric paintings. Researchers collected pigment, calcite crusts and comparative samples from unpainted sections of cave walls. The analysed sites contained different forms of rock art, including lines, dots, hand stencils, geometric shapes and figurative paintings. Most of the sampled motifs had been produced with red ochre, a mineral pigment frequently associated with the earliest artistic traditions of prehistoric Europe.
Ancient human mitochondrial and nuclear DNA was detected in samples from Escoural Cave in Portugal and Covarón Cave in Asturias, Spain. One of the most significant findings came from a pigmented calcite crust associated with a rock art panel at Escoural. The sample contained authentic ancient human genetic material without detectable animal DNA. Researchers believe this absence strengthens the possibility that the DNA was deposited through direct human contact rather than being transferred accidentally from nearby sediments.
Additional human DNA was recovered from unpainted wall sections at Escoural and Covarón. Some of those samples also contained genetic material from animals, including felids, rabbits and large herbivores. That mixture suggests the DNA may have reached the walls indirectly through sediment, water movement, dust or contact with materials originating elsewhere in the caves. Distinguishing direct from indirect deposition will be essential before scientists can associate individual genetic traces with specific human activities.
The researchers stressed that their results do not yet prove that the recovered DNA belonged to the people who created the paintings. A person could have touched or approached a wall centuries or even millennia after an image was produced. The genetic material could also reflect cleaning, ritual activity, sheltering or other uses of the cave unrelated to artistic production. The discovery therefore creates a new investigative pathway rather than providing a definitive identification of prehistoric artists.
The surviving traces were attributed to at least three women and one man, while another sample could not be assigned reliably to either sex. This information suggests that future studies may help reveal who entered particular areas of caves and whether certain activities were associated with specific groups. Scientists could eventually examine whether men, women or family communities occupied different underground spaces. Such evidence may challenge older interpretations that portrayed prehistoric cave activity as the exclusive domain of male hunters or ritual specialists.
The method could also illuminate how deeply ancient people ventured into cave systems and whether their movements followed recurring patterns. Genetic traces found on walls far from entrances might indicate deliberate exploration, ceremonial practices or specialized artistic work. Concentrations of DNA in particular chambers could reveal spaces of repeated human gathering. When combined with pigments, footprints, tools and archaeological sediments, wall DNA may help reconstruct behaviour with greater spatial precision.
The research employed highly sensitive laboratory procedures developed for ancient bones and sediments. Samples were processed using extraction methods capable of recovering extremely fragmented genetic molecules from mineral surfaces. Scientists then created single-stranded DNA libraries and enriched them for human mitochondrial material. Damage patterns at the ends of the recovered sequences helped distinguish genuinely ancient DNA from recent contamination introduced by researchers, visitors or modern handling.
Contamination remains one of the method’s greatest challenges. Many European caves have been visited by tourists, archaeologists and conservation workers for decades, sometimes without the protective measures required by modern genetic research. Human DNA can easily be transferred through skin cells, breath, dust and clothing. Future sampling will therefore require strict controls, detailed records of modern visitors and careful comparisons between ancient molecular damage and contemporary genetic signatures.
The discovery may prove especially valuable at archaeological sites where no human remains have survived. Cave floors can be disturbed by erosion, flooding, animal activity or excavation, while painted walls may remain comparatively stable. Recovering DNA from those surfaces could provide evidence of populations otherwise absent from the physical record. It may also reduce the need for extensive excavation because the samples can be collected through minimally invasive procedures.
The technique could eventually contribute to one of prehistoric archaeology’s most contested questions: whether Neanderthals created some of Europe’s earliest cave art. Certain paintings have been dated to periods preceding the widespread arrival of modern humans, but their authorship remains disputed. DNA recovered from securely dated pigment layers could provide powerful evidence, although researchers must first establish that the genetic material was deposited at the same time as the artwork.
The current study represents a proof of principle rather than the completion of that scientific objective. The recovered human DNA is at least 2,000 years old, but some sampled paintings and cave occupations are substantially older. Researchers must now determine how far back genetic preservation on rock surfaces can extend and under which environmental conditions it remains viable. Temperature, humidity, mineral composition and water movement may all influence whether DNA survives.
Cave walls are therefore emerging as more than visual supports for ancient art. They may preserve biological traces of the people who touched them, moved beside them and inhabited the spaces around them. This perspective transforms underground surfaces into archives where culture and genetics can be examined together. The finding does not yet reveal the identities of Europe’s earliest artists, but it provides science with a new way to search for them.
Cada silencio habla. / Every silence speaks.