Fallow deer and moose pay exorbitantly for their weapons, and for the stamina and energy needed to win fights during the rut, suffering gashes, infections, and depleted energy reserves. Above: Three-quarters of fallow deer bucks die without ever succeeding in defending territories, and 90 percent fail to mate even once in their lifetime. Below: Bull moose double their daily energetic demands while growing antlers, and a third die from injuries sustained during combat.

Emlen, Douglas J, Animal Weapons_ The Evoluti…, loc. 963