The contrast between Derryvree’s locally ice-free wetland and Castlepook’s mixed cave fauna suggests that Late Pleistocene Ireland was a shifting mosaic rather than a single frozen landscape. Equally intriguing is the possible cut-marked reindeer femur: it may indicate human activity, yet its disturbed context prevents conclusions about settlement. The article therefore highlights how environmental and archaeological evidence can illuminate movement without revealing its frequency or scale. How should researchers weigh the evidence of wetlands, animal dispersal and the Castlepook bone when considering whether human visits to Ireland were occasional crossings, seasonal journeys, or part of repeated networks during MIS 3?