Bighorn Sheep

NPS (Henthorne)

Bighorn sheep just off the road in the South District

Run first, look later; characteristic behavior of Bighorn sheep (Ovis canadensis). These magnificent creatures are the namesake of the canyon. 

Social creatures
Sheep are social creatures, traveling in bands ranging from 10 to 150 sheep. Sheep in the band tolerate any juveniles or ewes that follow. Ewes, which rarely weigh over 150 pounds, look after yearlings, acting as nannies. The first born spring lamb is the center of attention of the yearlings and the old, barren females.

Bighorns live on grasses and herbs like cows, they chew their cud. Their hair is hollow, which helps to trap body heat to protect them from cold weather. 

Locking Horns
Both ewes and rams have horns, but the ram’s horns are much larger and sometimes are fully curled. Bighorn Sheep keep their horns years round, unlike mammals with antlers, which are shed each year. Bighorn rams are armed with a pair of curled horns up to 45” in length and weighing as much as 30 pounds. 

These horns are used to clash or battle against competing rams to achieve dominance. Rams, which may weigh up to 300 pounds, can reach speeds up to 40 miles per hour when clashing. Battles may last for hours until one of the rams finally backs down.

Back From The Brink
After having been hunted for millennia in Bighorn Canyon, Bighorn sheep were extirpated from the area in the 1800s. They began to repopulate the area after a group was transplanted into the Bighorn Mountains in 1970.

Some of these sheep crossed the ice and by 1979 one mature ram and three ewes were living on the west side of Bighorn Canyon. In 1993, a population high of 210 were reported. By 2000, the population had dropped to between 85 -119 sheep.

Habitat Improvements
Following the recommendations of a U.S. Geological Survey team that studied the population dynamics and habitat use of 30 collared sheep during 2000–2003, habitat treatments such as burning and clearing of juniper have been carried out to improve otherwise suitable sheep habitat in the park.

Evidence of habitat improvement projects can be seen at Hillsboro, Barry’s Island, and Mustang Flats. Today there is a healthy population of between 150 to 200 sheep.