proportions of the Irish elk are similar to those of the cursorial addax, oryx, and saiga antelope. These include the relatively short legs, the long front legs nearly as long as the hind legs, and a robust cylindrical body. Cursorial saiga, gnus, and reindeer have a top speed of over , and can maintain high speeds for up to 15 minutes. Reproduction At Ballybetagh Bog, over 100 Irish elk individuals were found, all small antlered bucks. This indicates that bucks and does segregated during at least winter and spring. Many modern deer species do this partly because males and females have different nutritional requirements and need to consume different types of plants. Segregation would also imply a polygynous society, with stags fighting for control over harems during rut. Because most of the individuals found were juvenile or geriatric and were likely suffering from malnutrition, they probably died from winterkill. Most Irish elk specimens known may have died from winterkill, and winterkill is the highest source of mortality among many modern deer species. Bucks generally suffer higher mortality rates because they eat little during the autumn rut. For rut, a lean stag normally may have fattened up to , and would burn through the extra fat over the next month. Assuming a similar response to starvation as red deer, a large, healthy Irish elk stag with antlers would have had antlers under poor conditions; and an average sized Irish elk stag with antlers would have had antlers under poorer conditions, similar sizes to the moose. A similar change in a typical Irish elk population with prime stags having antlers would result in antler weights of or less in worsening climatic conditions. This is within the range of present-day wapiti/red deer (Cervus spp.) antler weights. Irish elk antlers vary widely in form depending upon the habitat, such as a compact, upright shape in closed forest environments. Irish elk likely shed their antlers and re-grew a new pair during mating season. Antlers generally require high amounts of calcium and phosphate, especially those for stags which have larger structures, and the massive antlers of Irish elk may have required much greater quantities. Stags typically meet these requirements in part from their bones, suffering from a condition similar to osteoporosis while the antlers are growing, and replenishing them from food plants after the antlers have grown in or reclaiming nutrients from shed antlers. The large