Irish elk

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Irish elk
Temporal range: Middle Pleistocene to Early Holocene, 0.781–0.008Ma
Überseemuseum Bremen 2009 250.JPG
Mounted skeleton in Bremen
Scientific classification
Kingdom: Animalia
Phylum: Chordata
Class: Mammalia
Order: Artiodactyla
Family: Cervidae
Genus: Megaloceros
Species: †M. giganteus
Binomial name
†Megaloceros giganteus
(Blumenbach, 1799)
Synonyms

†Megaceros giganteus
†Megaloceros giganteus giganteus

The Irish elk (Megaloceros giganteus),[1][2] was a species of Megaloceros and one of the largest deer that ever lived. Its range extended across Eurasia, from Ireland to northern Asia and Africa, but a related form is recorded from China during the Late Pleistocene.[3] The most recent remains of the species have been carbon dated to about 7,700 years ago in Siberia.[4] Although most skeletons have been found in Irish bogs, the animal was not exclusively Irish and was not closely related to either of the living species currently called elk - Alces alces (the European elk, known in North America as the moose) or Cervus canadensis (the North American elk or wapiti). Recent phylogenetic analyses support the idea of a sister-group relationship between fallow deer and the Irish Elk.[5][6] For this reason, the name "Giant Deer" is used in some publications.

Description[edit]

Restoration by Charles R. Knight

The Irish Elk stood about 2.1 metres (6.9 ft) tall at the shoulders carrying 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 kg (88 lb)). In body size, the Irish Elk matched the extant moose subspecies of Alaska (Alces alces gigas) as the largest known deer. The Irish Elk is estimated to have attained a total mass of 540–600 kg (1,190–1,320 lb), with large specimens having weighed 700 kg (1,500 lb) or more, roughly similar to the Alaskan Moose.[7][8][9] A significant collection of M. giganteus skeletons can be found at the Natural History Museum in Dublin.

Evolution[edit]

Physically, the Irish Elk is the heaviest known member of the “Old World deer”,[5] a division of the subfamily Cervinae whose groups the ”Old World deer” and “New World deer” are distinguished by foot structure rather than geographical origin.[10][citation needed][verification needed] Most remains of Irish Elk date from between 11,750 BP (Before Present)-with the first Megaloceros giganteus appearing about 400,000 years ago-and 10,950 BP.[11] Studies have shown they possibly evolved from M. antecedens. The earlier taxon — sometimes considered a paleosubspecies M. giganteus antecedens — is similar but had more complex and compact antlers.

The size of Irish Elk antlers are distinctive, and several theories have arisen as to their evolution. 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 has also been suggested that they eventually became so unwieldy that the Irish Elk could not carry on the normal business of life and so became extinct. It was not until Stephen Jay Gould's important 1974 essay on Megaloceros that this theory was tested rigorously.

Skeleton on display with antlers spanning 2.7 m (9 ft) and a mass of 40 kg (90 lbs).

Gould demonstrated that for deer in general, species with a 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. Irish Elk had antlers of the appropriate size in correlation to their massive bodies. 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.[12] In 1987, Kitchener presented evidence that Irish Elk antlers were in fact used for fighting.[13] In addition, the Irish elk's antlers had several functions such as being a display for attraction of females and dominance of rival males.[14] The elks shed their antlers and re-grew a new pair during mating season.[15] Not much is known about the Irish elk's mating system, but according to Cedric O'Driscall Worman, often the norm was low male/female ratio and of these males, few bred successfully. The number of offspring produced by a female Irish elk was only 1 per mating season. Ultimately, the decrease in energy intake by the Late Pleistocene, influenced the ability to produce for Irish elk females.[16]

Extinction[edit]

Traditionally, discussion of the cause of their extinction has focused on the antler size (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 humans was a contributing factor in the demise of the Irish Elk, as may have been the case with other 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). Others assume the ultimate cause of extinction may have been the adaptations for mineral metabolism that were beneficial to the Irish elk until vegetation changed.[17] But given the difficulty of recovering quantitative records of human hunting impacts from the sub-fossil record alone, the role of humans in the extinction of the Irish Elk is not yet clear.

Cave painting from Lascaux

Some research has suggested that a lack of sufficient high-quality forage caused the extinction of the elk. According to an article written by researchers Silvia Gonzalez, Andrew Kitcheneri, and Adrian Lister, in 2000, a reduction in forest density into the Late Pleistocene decreased nutritional selection and is believed to have led to a conflict between sexual selection and ultimately a decrease in antler and body size, which can explain what may have caused their demise.[18] 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. The males (and male deer in general) met this requirement partly from their bones, replenishing them from food plants 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, Giant Deer suffered from a condition similar to osteoporosis.[19] When the climate changed at the end of the last glacial period, 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.

Restoration

Simply blaming antler size for their extinction may not be entirely accurate. The most likely cause is the significantly shortened growing season seen toward the end of the Pleistocene Era. This reduced availability in nutrition resulted in the lowering of the female reproduction output by about 50%.[20]

However, the most recent specimen of M. giganteus in northern Siberia, dated to approximately 7,700 years ago - well after the end of the last glacial period - shows no sign of nutrient stress. They come from a region with a continental climate where the proposed vegetation changes had not (yet) occurred.[21]

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. Stuart et al. (2004) tentatively suggest that a combination of human presence along rivers and slow decrease in habitat quality in upland areas presented the last Irish Elk with the choice of either good habitat but considerable hunting pressure, or general absence of humans in a suboptimal habitat.

A folk memory of the Irish Elk was once thought to be preserved in the Middle High German word Shelch, a large beast mentioned in the 13th-century Nibelungenlied along with the then-extant aurochs (Dar nach schluch er schiere, einen Wisent und einen Elch, Starcher Ure vier, und einen grimmen Schelch / "After this he straightway slew a Bison and an Elk, Of the strong Wild Oxen four, and a single fierce Schelch."). The Middle Irish word segh was also suggested as a reference to the Irish Elk.[22][23] However, these interpretations are not conclusive.[24][25]

References[edit]

  1. ^ Geist, Valerius (1998): Megaloceros: The Ice Age Giant and Its Living Relatives. In: Deer of the World. Stackpole Books. ISBN 0-8117-0496-3
  2. ^ Lister, A.M. (1987): Megaceros or Megaloceros? The nomenclature of the giant deer. Quaternary Newsletter 52: 14-16.
  3. ^ Gould, S.J. "The misnamed, mistreated, and misunderstood Irish elk.". W.W. Norton. 
  4. ^ Stuart, A.J.; Kosintsev, P.A.; Higham, T.F.G. & Lister, A.M. (2004): Pleistocene to Holocene extinction dynamics in giant deer and woolly mammoth. Nature 431(7009): 684-689. PMID 15470427 doi:10.1038/nature02890 PDF fulltext Supplementary information. Erratum in Nature 434(7031): 413, doi:10.1038/nature03413
  5. ^ a b Lister, A. M.; Edwards, C. J.; Nock, D. A. W.; Bunce, M.; van Pijlen, I. A.; Bradley, D. G.; Thomas, M. G.; Barnes, I. (2005). "The phylogenetic position of the giant deer Megaloceros giganteus". Nature 438 (7069): 850–853. doi:10.1038/nature04134. 
  6. ^ van der Made, J.; Tong, H.W. (2008). "Phylogeny of the giant deer with palmate brow tines Megaloceros from west and Sinomegaceros from east Eurasia". Quaternary International 179 (1): 135–162. doi:10.1016/j.quaint.2007.08.017. 
  7. ^ http://www.motherearthnews.com/Nature-Community/1989-03-01/Of-Moose-Megaloceros-and-Miracles.aspx
  8. ^ R. D. E. Mc Phee, Extinctions in Near Time: Causes, Contexts, and Consequences p.262
  9. ^ [1]
  10. ^ http://www.britannica.com/EBchecked/topic/691201/Cervinae
  11. ^ http://www.m3motorway.ie/RelatedContent/file,14080,en.pdf
  12. ^ Gould, Stephen J. (1974): Origin and Function of 'Bizarre' Structures - Antler Size and Skull Size in 'Irish Elk', Megaloceros giganteus. Evolution 28(2): 191-220. doi:10.2307/2407322 (First page text)
  13. ^ Kitchener, A (1987). "Fighting behavior of the extinct Irish elk". Modern Geology 11: 1–28. 
  14. ^ Barnosky, Anthony (19 April 1985). "Taphonomy and Herd Structure of the Extinct Irish Elk, Megalocerous giganteus". Science. New 228 (4697): 340–344. doi:10.1126/science.228.4697.340. 
  15. ^ "Irish elk". 
  16. ^ Worman, C., & Kimbrell, T. (2008). Getting to the Hart of the Matter: Did Antlers Truly Cause the Extinction of the Irish Elk?. Oikos, (9), 1397. doi:10.2307/40235535
  17. ^ Moen, Ron; John Pastor; Yosef Cohen (1999). "Antler growth and extinction of Irish elk". Evolutionary Ecology Research: 235–249. 
  18. ^ Gonzalez, Silvia; Andrew Kitchener; Adrian Lister (15 June 2000). "Survival of the Irish elk into the Holocene". Nature 405: 753–754. doi:10.1038/35015668. 
  19. ^ Moen, R.A.; Pastor, J. & Cohen, Y. (1999): Antler growth and extinction of Irish Elk. Evolutionary Ecology Research 1: 235–249. HTML abstract
  20. ^ Worman, C., & Kimbrell, T. (2008). Getting to the Hart of the Matter: Did Antlers Truly Cause the Extinction of the Irish Elk?. Oikos, (9), 1397. doi:10.2307/40235535
  21. ^ Hughes, Sandrine; Hayden, Thomas J.; Douady, Christophe J.; Tougard, Christelle; Germonpré, Mietje; Stuart, Anthony; Lbova, Lyudmila; Carden, Ruth F.; Hänni, Catherine; Say, Ludovic (2006): Molecular phylogeny of the extinct giant deer, Megaloceros giganteus. Molecular Phylogenetics and Evolution 40(1): 285–291. doi:10.1016/j.ympev.2006.02.004 PDF fulltext. Supplementary data 1, DOC fulltext Supplementary data 2, DOC fulltext Supplementary data 3, DOC fulltext
  22. ^ Cuvier, Georges; Edward Griffith et al. (1827). The Animal Kingdom Arranged in Conformity with Its Organization. London: G. B. Whittaker. pp. 87–89. 
  23. ^ Hibbert, S. (Oct–Apr 1830). "Additional Contributions towards the History of the Cervus Euryce, or Fossil Elk of Ireland". The Edinburgh Journal of Science 2 (3): 314. 
  24. ^ Owen, Richard (1846). A History of British Fossil Mammals, and Birds. London: John Van Voorst. pp. 461–462. 
  25. ^ Gould, Stephen Jay (June 1974). "The Origin and Function of 'Bizarre' Structures: Antler Size and Skull Size in the 'Irish Elk,' Megaloceros giganteus". Evolution (Society for the Study of Evolution) 28 (2): 191. doi:10.2307/2407322. JSTOR 2407322. 

Further reading[edit]

Kurten is a paleo-anthropologist, and in this novel he presents a theory of Neanderthal extinction. Irish elk feature prominently, under the name shelk which Kurten coins (based on the aforementioned old German schelch) to avoid the problematic aspects of "Irish" and "elk" as discussed above. The book was first published in 1980, when the name "Giant Deer" was not yet being used widely.

External links[edit]