A bighorn is a large wild sheep that lives in the mountains of western North America, named for the massive curved horns that grow on the males. These horns can weigh up to 30 pounds and curl back around the sheep's head in a dramatic spiral, sometimes making a full circle. During mating season, male bighorns compete by charging at each other and crashing their horns together with tremendous force. The sound of these collisions can echo across mountain valleys and be heard from far away.

Bighorns are extraordinary climbers, able to navigate steep rocky cliffs that would be impossible for most animals. Their hooves have a hard outer rim surrounding a soft, rubbery center that grips rock surfaces like climbing shoes. They can leap across gaps of about 20 feet and climb slopes so steep they look nearly vertical.

Native Americans hunted bighorn sheep for thousands of years, and early European explorers in the American West often wrote about seeing large herds of them. Today, bighorns are less common than they once were, but you can still spot them in places like the Rocky Mountains, the Sierra Nevada, and the deserts of the Southwest. The bighorn sheep appears on the reverse side of the Nevada state quarter, making it one of America's most recognized wild animals.