The Irish elk was the giant Ice Age deer whose enormous antlers could span about 3.6 meters. Despite its name, it was neither limited to Ireland nor closely related to the modern elk of North America or Eurasia. Its scientific name is Megaloceros giganteus, and “giant deer” is another accurate common name, but “Irish elk” is the standard quiz answer.
The species ranged across much of Europe and parts of Asia during the Pleistocene. Its broad, flattened antlers were the largest known among deer and were probably used in display and competition between males. Fossil evidence shows that antler size changed with habitat and climate; animals living in more wooded environments tended to have smaller antlers than those in open landscapes.
The Irish elk survived into the early Holocene, with the youngest reliably dated remains found in western Russia at roughly 7,700 years old. Its disappearance likely involved several pressures, including climate and vegetation change, shrinking high-quality forage, and human hunting. The old idea that the antlers alone caused extinction is now considered too simplistic.