Ancient cave art discovery suggests first known humans in Ireland walked over from Wales

Researchers believe the first known humans to set foot on Ireland thousands of years ago were most likely from Wales, following the "exciting" discovery of ancient cave art.

During the most recent Ice Age, when much of the British Isles were beneath a vast continental glacier, the depleted sea levels opened a "lost land bridge" between modern-day Pembrokeshire and the south-east tip of Ireland, around Rosslare.

According to rock expert Dr George Nash, from Liverpool University, the opportunities presented by this pathway would have been too good for hunter gatherers to ignore.

Now, alongside an international team of experts, Nash has located eight cave sites in south-west Ireland featuring rock art dating back from at least 15,000 years ago, around 5,000 years before the previous oldest example of humans in Ireland.

Nash, who coordinated the Lost Land Bridge Project, said there would have been a forested and grassland plateau around 46 miles (76 km) 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.

Nash said he had always believed - from what he had gleaned throughout his career about human movement during the period - that it was inconceivable that people would not have utilised the opportunity the pathway presented.

This led him to assemble his multi-disciplinary team of experts from University College Dublin and the University of Adelaide, along with academics from Dubai, Wales and Portugal.

"Up until now the earliest evidence archaeologists had found - through accidental discovery - was from around 10,500 years ago, but everyone - not just me - knew that simply couldn't have been correct.

"We just weren't looking hard enough, and not in the right places. The principle we worked on was 'absence of proof isn't proof of absence'."

He said advances in artificial intelligence (AI) had been a game-changer.

"With the help of caving specialist Shane Diffily and digital mapping consultant Darren Lee, we were able to fill a computer algorithm with everything we knew about the characteristics of cave dwellings in south Wales and set it to work searching for similar sites in Ireland, without us trudging blindly around the countryside, hoping to bump into something which looked promising."

What their computer model spat out was 28 potential caves in south-west Ireland which the team investigated.

Eight of them were found to have cave art which they believe dates from at least 15,000 years ago and possibly much earlier, and around 5,000 years before the previous oldest example of humans in Ireland.

The team are currently unwilling to be more precise about the location of the caves, for fear that they may be vandalised or looted.

"We know that modern day south Wales was settled from around 35,000 to 40,000 years ago, by intrepid early modern humans from southern England, France and Spain, crossing the then dried-up land bridges of the English and Bristol Channels - seasonally settling in caves along the inhabitable strip of land stretching from Chepstow to St Davids," said Nash.

"Over 20,000 years their art progressed from primitive line drawings which may have been early tally charts, to more figurative and representative depictions of the world around them, and what we've found in Ireland is yet another progression from that."

The rock art which the Lost Land Bridge Project has uncovered includes engravings on the cave walls, paintings in ochre and charcoal and line sketches indented into clay and earth by fingertips.

Nash believes the growing population put pressure on humans to move ever more west and northwards.

"There were around 100 human-inhabited caves on The Gower Peninsula for example, in a time when the technology didn't yet exist for human groups to create their own free-standing dwellings.

"The ambient temperature within these caves would have remained between 10°C and 15°C all year round, so with bearskin covers and fires at the entrance - which also helped to ward-off predators - it would have been quite a cosy place to live, especially compared with the -20°C outside.

"Competition for these caves would have been intense.

"As family networks grew, knowledge of how to survive by following animal migration routes improved and they must have become bolder."

The Lost Land Bridge Project team believe the potential for more future discoveries is high.

"The sites we've currently explored are in south-west Ireland, but it's illogical to presume that early humans just bypassed Wexford, Waterford and Cork, and ploughed on west," said Nash.

"There must be more, and even earlier places which are just waiting for us to find them. This project is now pushing the boundaries of what we consider to be the final vestiges of a north-west European frontier. It's all very exciting."