Researchers believe the first humans to set foot on Ireland thousands of years ago may have come from Wales, according to a new study based on the discovery of ancient cave art. During the last Ice Age, when much of the British Isles were covered by a massive glacier, lower sea levels created a "lost land bridge" connecting modern-day Pembrokeshire in Wales to the southeast coast of Ireland near Rosslare. Dr. George Nash, a rock expert from Liverpool University, says this pathway would have been too valuable for early hunter-gatherers to ignore. Alongside an international team, Nash has identified eight cave sites in southwest Ireland with rock art dating back at least 15,000 years—around 5,000 years earlier than the previously known earliest human presence in Ireland. According to Nash, who led the Lost Land Bridge Project, the land bridge would have featured a forested and grassy plateau stretching about 46 miles (76 km) from coast to coast. Although summer temperatures were likely between -10°C and -20°C, the region would have supported large animals like wild horses, mammoths, bison, and reindeer, feeding on hardy plants growing in the nearly frozen soil. Nash believes early humans would have taken advantage of this corridor, leading him to form a multidisciplinary team of experts from institutions across the globe. "We weren't looking hard enough before," he said, emphasizing that the absence of evidence was not proof of absence. The project benefited from advances in artificial intelligence (AI), which helped the team identify potential cave sites more efficiently. Using a computer algorithm trained on the features of caves in south Wales, they identified 28 possible sites in southwest Ireland, eight of which were found to contain cave art dating back at least 15,000 years. The team is keeping the locations of the caves confidential to prevent vandalism or looting. According to Nash, early modern humans in south Wales were already settling in caves as early as 35,000 to 40,000 years ago, following seasonal migration patterns. The rock art found in Ireland appears to be a continuation of the artistic evolution seen in Wales, moving from simple line drawings to more detailed representations of the environment. The cave art discovered includes engravings on stone, paintings using ochre and charcoal, and line sketches pressed into clay and earth with fingertips. Nash suggests that as human populations grew, pressure to move further west and north would have increased. Caves in areas like The Gower Peninsula provided shelter, with temperatures around 10°C to 15°C, making them significantly more comfortable than the harsh winter conditions outside. As knowledge of survival techniques improved, early humans likely became more adventurous in their movements. The Lost Land Bridge Project team is optimistic about future discoveries. While the current findings are in southwest Ireland, Nash believes it is unlikely that early humans simply bypassed other regions like Wexford, Waterford, and Cork. "There must be more, and even older sites waiting to be found," he said, emphasizing that the project is expanding the understanding of the north-west European frontier. The research continues to reveal exciting new insights into the early human presence in Ireland.