Irish elk

Abstract: Adult male Irish elk (Megaloceros giganteus) grew the largest antlers of any extinct or extant cervid. These antlers have often been implicated in the extinction of the Irish elk, although the eVects of antler growth on Irish elk physiology have not been analysed quantitatively. We used a simulation model of energy and mineral metabolism to compare nutritional requirements for antler growth in Irish elk and moose (Alces alces), the largest extant cervid. The model simulates intake, metabolism, deposition, and excretion of energy, nitrogen, ash, calcium and phosphorus with mass balance for each of these nutrients on a daily time step. Predicted energy requirements for antler growth by moose are half as large as energy requirements for summer fat and protein deposition. In contrast, the predicted energy requirements for antler growth by Irish elk were about 75% as large as energy requirements for summer fat and protein deposition. Irish elk antlers weighing 40 kg at the end of velvet shedding would have contained 2.1 kg nitrogen, 7.6 kg calcium and 3.8 kg phosphorus. The nitrogen requirements for antler growth were met by forage intake. The model predicts that, to grow 40 kg antlers in a 150 day period, more than 60 g of calcium and more than 30 g of phosphorus were deposited in antlers daily for 60 consecutive days when antler mineralization rate was highest in mid-summer. Simulated Irish elk depleted skeletal mineral reserves to support antler growth more than extant moose, even when hypothesized adaptations to reduce skeletal mineral resorption were implemented. Even though Irish elk Wt the allometric relationship between antler size and body size in extant cervids, mineral metabolism does not scale allometrically in the same manner. About 6% of the calcium and 10% of the phosphorus in the antler were resorbed from the skeleton because dietary intake of minerals was insuYcient to meet requirements for antler mineralization. The minerals resorbed from the skeleton in summer would have to be replenished by dietary intake over the following winter. Pollen records document a shift in plant species composition from a tall willow‐spruce community during the Allerod interstadial to a tundra during the Younger Dryas cold episode with reduced forage density coincident with the extinction of the Irish elk about 10,600 years before present (b.p.). The reduction in forage density would have made replenishing calcium and phosphorus in the skeleton even more diYcult, as well as making it more diYcult for male Irish elk to replenish fat reserves depleted during the rut. Sexual selection pressures for larger antlers and larger body size were opposed by selection pressures for smaller antlers and smaller body size imposed by environmental change. We suggest that the inability to balance these opposing selection pressures in the face of rapid environmental change contributed to extinction of the Irish elk 10,600 years b.p.

Abstract: "Size," Julian Huxley once remarked, 4'has a fascination of its own" The fame of the "Irish Elk" rests squarely on the immensity of its antlers, the largest the world has ever known Dr Molyneux, in the first scientific description of the Irish Elk, stood in awe before "these spacious horns" ( 1697, p 493) and lamented that "so singular and beautiful an ornament" (1697, p 501) had disappeared from Ireland during "those savage ages of the world" (p 501), now thankfully passed The gigantic antlers, spreading 10 to 12 feet in large stags, have generated a fund of legend and anecdote (Gould, 1973) They have served as gateposts to the homes of Irish gentry and as temporary bridges to span rivulets They have inspired the admiration of kings (Molyneux, 1697, p 495) and the competition of Victorian gentlemen stocking their trophy rooms But, more important in our context, they have continually confronted evolutionary theory as an outstanding datum demanding some explanation There is scarcely a textbook in evolutionary biology that does not illustrate some important principle with a well chosen pair of antlers The Irish Elk, like the Holy Roman Empire, is misnamed in all its attributes: it is neither exclusively Irish nor an elk It is a Pleistocene deer of the subfamily Cervinae; (Alces alces, the European moose, is called an "elk" in England; the superficial similarity of its large antlers to those of Megaloceros inspired the vernacular misnomer) Almost all the fine specimens that adorn museums and homes throughout the world are from Ireland They are found in lake deposits of the Aller6d interstadial (ca 12,000 to I1,000 BP) and retain their excellent preservation by their insulation below the, overlying peat (Kelly, 1726; Adams, 1878; Williams, 1878) Yet the species was widely spread through Europe, northern Asia and northern Africa (Martin and Guilday, 1967); a related form inhabited China (Shikama, 1939; Kurten, 1968) There has been much debate about the time of its extinction Most authorities agree that Megalocer,os was already extinct in Ireland before the arrival of man about 10,000 years ago (Owen, 1846; Savage, 1966) Elsewhere, it may have lived to historic times Sizer (1962) and Kurten (1968) cite finds from Syria and southern Russia indicating possible survival until ca 3000-2 500 BP Earlier authors even tried to identify it with the "schelch" of the Nieb,elungenlied, but this notion has long been abandoned (Nehring, 1892) Many nineteenth century authors, following the typologies of their time, erected formal subdivisions within Megaloceros giganteus Lyddeker (1898) recognized five races and other authors elevated these to specific rank I do not think that anyone defends these subdivisions today (see Kirschner, 1936 and Charlesworth, 1957 for a discussion of this issue) The ancestry of Megaloceros has not been fully determined Reynolds (1929) and Kahlke (1956) suggest a Siberian origin Its immediate progenitors may be found among the Praemegaceros verticornis complex of the lower Pleistocene (Soergel, 1927; Reynolds, 19229); other views are expressed by Kahlke (1951, 1956) and Azzaroli (1953) Most authors believe that the palmated fallow deer (Damna dama) is

Abstract: Fossils of the late Pleistocene elk Megaloceros giganteus from Ballybetagh bog, near Dublin, Ireland, indicate that males segregated from females during winters. The segregation implies seasonal rutting and polygynous mating and is consistent with the idea that large antlers functioned for social display. Within male groups, winterkill was the chief cause of death and was highest among juveniles and small adults with small antlers. There is no evidence to support the popular conception that heavy antlers caused animals to drown or become mired.