Bighorn Sheep (Ovis canadensis)

Bighorn Sheep are often seen along U.S. Highway 16 within the boundaries of Jewel Cave National Monument. Our Historic Area is one of their favorite places to spend their time.

NPS/ Neal Herbert

 

Bighorn rams are sometimes spotted along U.S. Highway 16 approaching Jewel Cave National Monument or along the 3.5 mile Canyons trail loop.

NPS/ Neal Herbert

Bighorn Sheep
Ovis canadensis

Brief bio

• Bighorn sheep are native to the black hills but the original population was lost in the early 1900s due to over hunting and the introduction of diseases, like pneumonia, from domestic sheep.
• In 2001, there was a successful reintroduction of Bighorn Sheep into Hell Canyon immediately west of Jewel Cave National Monument. Today the population of sheep in the area is healthy is rising.

Size and description

• Bighorn sheep have easily identifiable physical differences between genders. Females, called ewes, will be smaller in size; especially noticeable around the neck and chest which will be much more slender than on a male, called a ram.
• Rams will stand 2.5-3.5 feet at the shoulder and weigh 125-325 lbs.
• Ewes are smaller and will weigh from 75-150 lbs. and stand 2.5-3 feet at the shoulder.
• Coloration will the same for both genders. Brown bodies with a small tail and white rump and a white muzzle.
• The most obvious way to identify the difference between rams and ewes are the horns for which they are named. Mature rams sport massive, curled, heavily ridged horns that can measure 45 inches in length. Ewes are also horned, with much smaller and thinner and slightly curved horns measuring 7-13 inches in length.

 

Bighorn sheep lambs are born in the springtime and are totally dependent on their mothers for their first few months of life. They can be seen running around and playing on the canyon walls of nearby Hell Canyon.

NPS/ Jacob W. Frank

Behavior

• Bighorn sheep are largely gregarious. Outside of the rut, rams live together in a herd separate from the herd of ewes, lambs and yearlings.
• During the rut, rams will compete for dominance and breeding rights. Males will stand about 45 feet from each other and charge, at the last minute they will rear up on their hind legs and crash their massive horns into each other until one of them submits.
• It is estimated the force exerted when rams butt heads is 60 times higher than the force it would take to fracture a human skull.

Diet

• Bighorn sheep are primarily grazers, though when grass is not as readily available they will browse shrubs and other vegetation.
• Important food types for bighorn sheep are grasses, sedges, forbs, and shrubs.

Interactions with other animals

• Bighorn sheep are especially vulnerable in their first year of life. Predators like coyotes, bobcats, and mountain lions will readily take advantage of young bighorn sheep. Adult bighorns are still under threat from mountain lions.
• Disease from domestic sheep is hugely detrimental to wild herds of bighorn sheep, who are introduced to these diseases from shared rangeland and do not have a strong enough immune system to combat them.