Castlepook’s Deep Winter
Archived: 10 September 2026
Around 31,819 BCE, Ireland was a climatically unstable Late Pleistocene landscape, not a place with recorded human history. Lower seas, shifting ice margins and episodic connections shaped animal movement, although routes remain uncertain. Derryvree deposits in Fermanagh preserve evidence of cold, open tundra vegetation, freshwater habitats and an ice-free interval later buried by glaciers. Castlepook Cave in Cork contains remains of reindeer, mammoth, giant deer, hyaena and other cold-stage animals, demonstrating varied fauna before the Last Glacial Maximum. A marked reindeer femur may indicate human butchery, but cannot prove settlement. Later glaciation destroyed much evidence, leaving uncertainty central to interpretation.