Harems break up when the rut ends.
Feeling weak from the rut and knowing their antlers make them stand out, the bulls stand a better chance against predators by hiding out on their own or in small groups. Cows and calves regroup in herds led by older, experienced cows. In the western United States, lead cows also guide the herd from their summer range to winter range and back on established migration routes. Not all elk have to migrate like they do in the Rocky Mountains. If they have enough food, water, shelter and space, elk will stay in the same area year-round.