Wildlife photography of two bull elk fighting with their antlers in heavy snow in Yellowstone National Park

As heavy snows turn Fall to Winter, a pair of bull elk engage in antler wrestling to settle a dispute. When antlerless, Elk fight with their hooves, but this actually inflicts more injury. As bulls spend the Winter together, retaining antlers all Winter means fewer injuries and good defense against predators. The larger the antler rack, the longer the rack is retained, so these enormous bulls are at the apex of their social structure with preferential access to the best feeding grounds and in the Fall, females.