Although large numbers of skeletons have been found in Irish bogs, its common name, Irish Elk, is misleading as the animal was not exclusively Irish, and neither was it closely related to either of the living species currently called elk; for this reason, the name "Giant Deer" is preferred in more recent publications. Megaloceros giganteus first appeared about 400,000 years ago.
The Irish Elk stood about 2.1 metres (6.9 ft) tall at the shoulders, and it had the largest antlers of any known cervid (a maximum of 3.65 m (12.0 ft) from tip to tip and weighing up to 40 kilograms (88 lb)). In body size, the Irish Elk matched the extant moose subspecies of Alaska (Alces alces gigas) as the largest known deer. A significant collection of M. giganteus skeletons can be found at the Natural History Museum in Dublin.