Bugling is a male dominance display that attracts females and states the rank of the male. Rival males respond by bugling back. Bulls may actually spar with challengers, after first demonstrating threat postures, then thrashing the ground with their antlers. A large percentage of the cow elk become pregnant each year. The rut is an intense time for bulls.
Dominant males expend a considerable amount of energy.
The price for passing on their genes consists of entering winter with weight loss and in some instances a depleted physical condition. Snowfall in the high country prompts the elk to move from their summer ranges to lower elevations. To reach the grasses they eat, elk paw through snow. Their feeding is hampered by deep snow or icy conditions. Throughout the fall, elk in Grand Teton and Southern Yellowstone National Park, adjacent forest areas to the north and east follow drainages and ridge lines as they funnel to wintering grounds.