American bighorns fighting. View of male American bighorns or mountain sheep, Ovis canadensis, fighting on rutting ground. Both the males and females of this species have spiral horns which can reach 50 cm in length on the ram. The status of each male within the flock is settled by long duels between males using these horns. The fights occur during the mating season (rut). American bighorns are found on pasture in the Rocky Mountains where they feed on grasses. Photographed in Yellowstone National Park, Wyoming, USA.