Castlepook’s Reindeer Horizon
Archived: 9 September 2026
31,923 BCE is an approximate modern label within Marine Isotope Stage 3, not a datable Irish event. Castlepook Cave in north Cork preserves disturbed pre-Last Glacial Maximum faunal remains, including reindeer, bears, wolves, Arctic foxes, lemmings, giant deer, mammoths and hyaenas. These animals indicate a fluctuating, open, cold environment rather than permanent ice cover. A reindeer femur dated to 31,000 BCE may bear a stone-tool butchery mark, potentially Ireland’s earliest human evidence. However, no associated tools, hearths or settlement survive, and the mark remains contested. The evidence suggests possible hunter-gatherer visits, not proven occupation, during a landscape transformed by glaciation.



