as the third largest known deer, after the extinct Cervalces latifrons and Cervalces scotti. Nonetheless, compared to Alces, Irish elk appear to have had a more robust skeleton, with older and more mature Alces skeletons bearing some resemblance to those of prime Irish elk, and younger Irish elk resembling prime Alces. Likely due to different social structures, the Irish elk exhibits more marked sexual dimorphism than Alces, with Irish elk bucks being notably larger than does. In total, Irish elk bucks may have ranged from , with an average of , and does may have been relatively large, about 80% of buck size, or on average. The distinguishing characters of M. giganteus include concave frontals, proportionally long braincase, proportionally short front section of the skull (orbitofrontal region), alongside the absence of upper canines and the molarisation of the lower fourth premolar (P4). The skull and mandible of the Irish elk exhibit substantial thickening (pachyostosis), with the early and complete obliteration of cranial sutures. Based on Upper Palaeolithic cave paintings, the Irish elk seems to have had overall light colouration, with a dark stripe running along the back, a stripe on either side from shoulder to haunch, a dark collar on the throat and a chinstrap, and a dark hump on the withers (between the shoulder blades). In 1989, American palaeontologist Dale Guthrie suggested that, like bison, the hump allowed a higher hinging action of the front legs to increase stride length while running. Valerius Geist suggested that the hump may have also been used to store fat. Localising fat rather than evenly distributing it may have prevented overheating while running or in rut during the summer. Habitat It was not exclusive to Ireland. Rather, it was so named because the most well-known and best-preserved fossil specimens have been found in lake sediments and peat bogs in Ireland. The Irish elk had a far-reaching range, extending from the Atlantic Ocean in the West to Lake Baikal in the East. They do not appear to have extended northward onto the open mammoth steppe, rather keeping to the boreal steppe-woodland environments, which consisted of scattered spruce and pine, as well as low-lying herbs and shrubs including grasses, sedges, Ephedra, Artemisia and Chenopodiaceae. Palaeobiology Physiology In 1998, Canadian biologist Valerius Geist hypothesised that the Irish elk was cursorial (adapted for running and stamina). He noted that the Irish elk physically resembled reindeer. The body