The distribution of M. giganteus is thought to have been strongly controlled by climactic conditions. The range of the Irish elk appears to have collapsed during the Last Glacial Maximum (LGM), with few remains known between 27,500 and 14,600 years ago, and none between 23,300 and 17,500 years ago. Known remains substantially increase during the latest Pleistocene, where it appears to have re-colonized most of its former range, with abundant remains in the UK, Ireland, and Germany. A 2021 study found that M. giganteus saw a progressive decline in mitochondrial genome diversity beginning around 50,000 years ago, which accelerated during the LGM.
