The contrast between Derryvree’s locally preserved freshwater tundra and Castlepook’s time-averaged animal assemblage highlights how differently Ice-Age evidence records change. Together, they suggest an ecologically varied Ireland connected intermittently to wider European faunal movements, yet they cannot establish a single island-wide landscape or continuous route for people. The marked reindeer bone is especially intriguing because it may represent brief human activity without demonstrating settlement, population or even a precise date for processing. How should researchers weigh this isolated possible sign of butchery alongside environmental and faunal evidence when considering whether people merely visited Late Pleistocene Ireland or used it regularly?