The extinct giant deer with enormous Ice Age antlers is commonly called the Irish elk.
Its scientific name is Megaloceros giganteus, and it was one of the largest deer ever known. Despite its common name, it was neither especially close to modern elk nor confined to Ireland. Its range stretched across northern Eurasia, from Ireland to the region of Lake Baikal in Siberia. Ireland produced especially abundant fossil remains because antlers and skeletons were preserved in peat bogs.
The species is famous for antlers that could span more than 4.2 metres. These enormous structures were shed and regrown annually by males, as in living deer. Their size likely helped with display and competition, rather than directly causing extinction. The Irish elk survived into the early Holocene, with the youngest remains dating to roughly 7,700 years ago in western Russia. Its closest living relatives are generally considered fallow deer, not moose or North American elk.