Yellowstone National Park warned visitors to the area this weekend to be wary of randy elks looking to mate. The annual “elk rut” extends from early September to mid-October where male elk “announce their availability” by bugling to wanton females. The males then challenge each other in what often become horn-clashing battles to try to impress their potential partners, according to the National Park Service. Park authorities warn that curious human onlookers could get caught up in the commotion.