From fossil skeletons it's possible to determine the body sizes and proportions of these giant deer, and Moen, Pastor, and Cohen fit these values into their model to estimate how much the animals must have paid for the growth of their incredible weapons. Not surprisingly, Irish elk antlers appear to have been impressively costly, half again as much as the antlers of moose or caribou, and demanding almost two and a half times the basal metabolic energy requirements each day to grow. The calcium and phosphorus demands were severe, and seasonal osteoporosis was likely especially dire in this species.

Emlen, Douglas J, Animal Weapons_ The Evoluti…, loc. 320