Ancient Cave Markings in Ireland Could Rewrite the Island's Entire Human History

Paintings in the Dark, Thousands of Years Before Anyone Was Supposed to Be There

Imagine walking into a limestone cave in southwestern Ireland and finding paintings of mammoths and deer on the walls — made by human hands at least 15,000 years ago, at a time when the island was widely believed to be uninhabited. That is exactly what researchers with the Lost Land Bridge Project say they have found, and the implications for our understanding of prehistoric human migration are staggering.

The discoveries involve prehistoric markings located in eight caves in Ireland that could potentially date as far back as 15,000 years ago. Dr. George Nash, a rock art specialist at the University of Liverpool who coordinated the Lost Land Bridge Project, says the findings push back the earliest confirmed human presence in Ireland by roughly 5,000 years — prior to this, the oldest known archaeological evidence of humans on the island was roughly 10,500 years old.

Walking to Ireland on Dry Land

The international team behind the Lost Land Bridge Project believes the finds could provide evidence that some of Ireland's earliest known inhabitants travelled westwards from Wales during the last Ice Age, when sea levels were substantially lower than today. Depleted sea levels opened a lost land bridge between modern-day Pembrokeshire and the south-east tip of Ireland around Rosslare, creating a forested and grassland plateau roughly 46 miles coast-to-coast.

With summertime temperatures typically -10°C to -20°C, Nash said the pathway would have supported wild horses, mammoth, bison, reindeer and other large herbivores, which fed off the hardy sedges, mosses and lichens growing through the fertile, but near-frozen soil. For mobile hunter-gatherer communities dependent on animal migration and seasonal resources, Nash argues that the landscape would have presented an opportunity that was difficult to ignore. Nash noted that south Wales had itself been settled between 35,000 and 40,000 years ago by early modern humans moving up from southern England, France and Spain, and that the art traditions found in the Irish caves represent a further evolution of what those communities developed over thousands of years.

An Algorithm Leads the Way

Rather than conducting a blind field search, the team fed a computer algorithm with data on the characteristics of cave dwellings in south Wales, allowing it to flag comparable sites in Ireland. The model identified 28 candidate caves, and eight were confirmed to contain rock art. The use of artificial intelligence to narrow down the search represents a significant methodological leap for archaeologists working across vast, rugged terrain.

The rock art uncovered by the Lost Land Bridge Project includes engravings on the cave walls, paintings in ochre and charcoal, and line sketches indented into clay and earth by fingertips. The art depicts possible animals such as deer and mammoth. The precise locations of the caves are kept secret to protect them against possible vandalism.

Exciting, But Not Yet Settled Science

The researchers have not yet published numerical dates for the cave art in a peer-reviewed paper, and geological reconstructions disagree over whether people could actually have walked from Wales to Ireland at the proposed time. A separate peer-reviewed study of Bacon Hole in the Gower, Wales, used pigment analysis and uranium-thorium dating and found evidence dating back at least 17,100 years — but to offer real evidence that the Irish journey took place, direct dating of the Irish cave art is still needed.

As investigations continue, Nash and the research team say that reliable dating of the art will be an important next step toward determining how early these prehistoric artists might have arrived, and once that testing is completed, it will help determine whether the timescales on the arrival of Ireland's earliest human inhabitants will indeed be pushed back by thousands of years. The initial discoveries at the eight cave locations may represent only a small portion of the long-overlooked archaeological evidence throughout Ireland. If the dating holds, what was once considered empty, frozen wilderness may turn out to have been a canvas for some of humanity's earliest artists — people bold enough to walk to the edge of the known world and leave their mark on it.