information:extraction, structural:expansion
Pleistocene

Large deer with impressive antlers evolved during the early Pleistocene, probably as a result of abundant resources to drive evolution. The early Pleistocene cervid † Eucladoceros was comparable in size to the modern elk. † Megaloceros (Pliocene–Pleistocene) featured the Irish elk (M. giganteus), one of the largest known cervids. The Irish elk reached 2 metres (6 + 1 ⁄ 2 ft) at the shoulder and had heavy antlers that spanned 3.6 metres (11 ft 10 in) from tip to tip. These large animals were traditionally thought to have faced extinction due to conflict between sexual selection for large antlers and body and natural selection for a smaller form, but a combination of anthropogenic and climatic pressures is now thought to be the most likely culprit. Meanwhile, the moose and reindeer radiated into North America from Siberia.