Fossil range: Middle to Late Pleistocene
The Irish Elk or Giant Deer, Megaloceros giganteus was a species of Megaloceros and one of the largest deer that ever lived. Johann Friedrich Blumenbach ( May 11, 1752 – January 22, 1840) was a German doctor and Physiologist, Year 1799 ( MDCCXCIX) was a Common year starting on Tuesday (link will display the full calendar of the Gregorian calendar (or a In Scientific nomenclature, synonyms are different Scientific names used for a single Taxon. The Deer of the Genus Megaloceros - literally "Great Horn" see also Lister (1987 - were found throughout Eurasia from the late A deer is a Ruminant Mammal belonging to the family Cervidae. Its range extended across Eurasia, from Ireland to east of Lake Baikal, during the Late Pleistocene. For the superstate in George Orwell 's novel see Nations of Nineteen Eighty-Four. Lake Baikal (о́зеро Байка́л Ozero Baykal, ˈozʲɪrə bʌjˈkɑl Байгал нуур Baygal nuur) is in Southern Siberia in Russia The Late Pleistocene (also known as Upper Pleistocene or the Tarantian) is a stage of the Pleistocene Epoch. The latest known remains of the species have been carbon dated to the early Holocene about 7,700 years ago. Radiocarbon dating is a Radiometric dating method that uses the naturally occurring Radioisotope Carbon-14 (14C to determine the age of The Holocene is a Geological epoch which began approximately 10000 years ago (about 8000 BC  Its old common name Irish Elk is misleading. Although large numbers of skeleton have been found in Irish bogs, 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. Ireland (pronounced /ˈaɾlənd/ Éire) is the third largest island in Europe, and the twentieth-largest island in the world A bog or mire is a Wetland type that accumulates Acidic Peat, a deposit of dead plant material &ndash usually Mosses but also The elk, or wapiti ( Cervus canadensis) is one of the largest Species of Deer in the world and one of the largest Mammals in Megaloceros giganteus appeared for the first about 400,000 years ago. It evolved possibly from M. antecedens. The earlier taxon — sometimes considered a paleosubspecies M. A taxon (plural taxa) or taxonomic unit, is a name designating an organism or a group of Organisms In Biological nomenclature according to A chronospecies is a Species which changes physically morphologically, genetically, and/or behaviorally over time on an evolutionary scale such giganteus antecedens — is similar but had more compact antlers.
The Irish Elk stood about 2. 1 metres (6. The metre or meter is a unit of Length. It is the basic unit of Length in the Metric system and in the International 9 ft) tall at the shoulders, and it had the largest antlers of any known cervid (a maximum of 3. A foot (plural feet or foot; symbol or abbreviation ft or sometimes &prime – the prime symbol) is a non-SI unit Antlers are the usually large and complex horn -like appendages of most Deer species mostly worn by males only for some species such as Caribou by both A deer is a Ruminant Mammal belonging to the family Cervidae. 65 m (12. 0 ft) from tip to tip and weighing up to 40 kilograms (88 lb)). The pound or pound-mass (abbreviation lb, lbm, or sometimes in the United States #) is a unit of Mass A significant collection of M. giganteus skeletons can be found at the Natural History Museum in Dublin. Ireland 's Natural History Museum ( Músaem Stair an Dúlra) a branch of the National Museum is housed on Merrion Street in Dublin. Dublin (ˈdʌblɨn/ /ˈdʊblɨn or /ˈdʊbəlɪn/, bˠalʲə aːha klʲiəh or cliə(ɸ is both the largest city and capital of Ireland.
The size of Irish Elk antlers is distinctive, and several theories have arisen as to their evolution. eVolution is the third Album by eLDee, it was due to be released in 2008 One theory was that their antlers, under constant and strong sexual selection, increased in size because males were using them in combat for access to females; it was also suggested that they eventually became so unwieldy that the Irish Elk could not carry on the normal business of life and so became extinct. Sexual selection is the Theory proposed by Charles Darwin that states that certain evolutionary traits can be explained by Intraspecific competition However, it was not until Stephen Jay Gould's important 1974 essay on Megaloceros that this theory was tested rigorously. Stephen Jay Gould (September 10 1941 &ndash May 20 2002 was a prominent American paleontologist, evolutionary biologist, and historian of science
Gould demonstrated that for deer in general, species with larger body size have antlers that are more than proportionately larger, a consequence of allometry, or differential growth rate of body size and antler size during development. Allometry is the study of the relationship between Size and Shape, first outlined by Otto Snell in 1892 and Julian Huxley in 1932 In fact, Irish Elk had antlers of just the size one would predict from their body size. Note this does not mean that sexual selection played no part in maintaining large antler size, only that the antlers of the species' ancestors were already large to begin with. Indeed, Gould concluded that the large antler size and their position on the skull was very much maintained by sexual selection: They were morphologically ill-suited for combat between males, but their position was ideal to present them to intimidate rivals or impress females. Unlike other deer, M. giganteus did not even have to turn its head to present the antlers to best effect, but could accomplish this by simply looking straight ahead. 
Discussion of the cause of their extinction has focused on the antlers (rather than on their overall body size), which may be due more to their impact on the observer than any actual property. Some have suggested hunting by man was a contributing factor in the demise of the Irish Elk as it was with many prehistoric megafauna, even assuming that the large antler size restricted the movement of males through forested regions or that it was by some other means a "maladaptation" (see Gould 1974). Megafauna are species of large Animals ( Greek μεγας large + modern Latin fauna animal A maladaptation is an Adaptation that is (or has become more harmful than helpful But evidence for overhunting is equivocal, and as a continental species, it would have co-evolved with humans throughout its existence and presumably have adapted to their presence.
More recent research pointed out that high amounts of calcium and phosphate compounds are required to form antlers, and therefore large quantities of these minerals are required for the massive structures of the Irish Elk. Calcium (ˈkælsiəm is the Chemical element with the symbol Ca and Atomic number 20 A phosphate, an Inorganic chemical, is a salt of Phosphoric acid. The males (and male deer in general) met this requirement partly from their bones, replenishing them from foodplants after the antlers were grown or reclaiming the nutrients from discarded antlers (as has been observed in extant deer). Thus, in the antler growth phase, male deer from Ireland were suffering from a condition similar to osteoporosis. Osteoporosis is a Disease of Bone that leads to an increased risk of fracture. 
When the climate changed at the end of the last Ice Age, the vegetation in the animal's habitat also changed towards species that presumably could not deliver sufficient amounts of the required minerals, at least in the western part of its range. An ice age is a period of long-term reduction in the Temperature of the Earth 's surface and atmosphere resulting in an expansion of continental Ice sheets The most recent specimen of M. giganteus in northern Siberia, dated to 7,700 years ago - well after the end of the last Ice Age -, shows no sign of nutrient stress. This is actually quite unsurprising, as they come from a region with continental climate where the proposed vegetation changes had not (yet) occurred. Continental climate is a Climate that is characterized by Winter Temperatures cold enough to support a fixed period of Snow cover each Year 
In conclusion, it is easy to advance a number of hypotheses regarding the disappearance of the more localized populations of this species. The situation is less clear regarding the final demise of the Irish Elk in continental Eurasia east of the Urals however. Stuart et al. (2004) tentatively suggest that a combination of human presence along rivers and slow decrease in habitat quality in upland presented the last Irish Elk with the choice of good habitat but considerable hunting pressure, or general absence of humans in suboptimal habitat.