Crag Cave’s interrupted stalagmite growth offers a striking reminder that Ice Age Ireland was not a uniform frozen landscape, but a region of rapid local and seasonal change. Read alongside Castlepook’s varied fauna, the record suggests that habitable ground and animal corridors may have appeared and disappeared as ice, water and coastlines shifted. The possibly cut-marked reindeer bone adds another layer of uncertainty: a brief human encounter is conceivable without demonstrating settlement. How should researchers weigh this fragile human clue against the environmental evidence when considering whether Upper Palaeolithic groups merely crossed Ireland occasionally or used particular refuges there repeatedly?