The Rocky Mountain bighorn sheep (Ovis Canadensis) is one of four native sheep species that inhabit the North American continent and the only one that resides in Colorado. Bighorn sheep play a key role in bringing tourist and revenue into the state.
Characteristics and Habits
Known for their large muscular build, bighorn sheep can weigh from 100 to 320 pounds and can reach a standing height of three feet at the shoulders. Rams, or male sheep, have massive curled horns that often reach one complete curl before the growing process slows. Ewes, or female sheep, have slender horns that are much shorter and straighter. Bighorn sheep fur comes in many different shades of brown depending on their home range, but the animals almost always have a white underbelly, rump patch, muzzle, and eye patch. They also have a winter coat that they are able to shed in the summer months, allowing them to flourish in a variety of habitats.
During the summer, these majestic creatures can be found in the high-elevation (6,000–14,000 ft.) portions of the Rocky Mountains, from Canada to New Mexico. Their remarkable climbing abilities allow bighorns to scale cliffs or canyon walls to stay out of reach of predators. Their predators include coyotes, wolves, bobcats, and, predominantly in Colorado, mountain lions. When the cool, crisp air of autumn arrives, the sheep move to mountain pastures at lower elevations (2,500–5,800 ft.) to gain better access to forage and escape the heavy winter snowfall.
Rocky Mountain bighorn sheep are herbivores, meaning that they gain most of their energy by eating plant material. Primarily, they eat grasses. In the winter months, when the mountains of Colorado are snow-covered, the sheep turn to woody shrubs and forbs to survive.
Mating season occurs from November through December, taking place during the migration from high to low elevation. Pregnancy lasts 180 days, leading to the birth of one lamb sometime in May. Rocky Mountain bighorn sheep are most vulnerable during this time period, and this is also the time that they are most likely to interact with humans.
Interaction with People
In the late nineteenth century, during Colorado’s rapid industrial development, something unprecedented was happening deep in the Rocky Mountains. For the first time in Colorado’s history, the bighorn sheep population suffered from hunting, human encroachment on their habitat, and the introduction of new diseases brought by domesticated sheep herds. These diseases included scabies, chronic frontal sinusitis, internal nematode parasites, pneumophilic bacteria, foot rot, parainfluenza 111, bluetongue, and contagious echthyma. Since domestic and bighorn sheep are both in the same genus, diseases are easily transmittable between the two species. In the late 1800s and early 1900s, scabies and pneumophilic bacteria killed hundreds of Colorado bighorns. By 1950 there were only an estimated 2,200 bighorn remaining in Colorado. This was the lowest population level ever recorded.
In the mid-1950s, after extensive research by the newly created Colorado Division of Wildlife, large herds were reintroduced into central Colorado. Fueled by the reintroductions and new management practices, bighorn sheep numbers rebounded. In fact, with seventy-nine separate breading herds and an estimated total of 7,040 individuals, Colorado enjoyed the largest number of Rocky Mountain bighorn sheep in the United States. It was also estimated that roughly half of the herds within the state were native, meaning that they were completely composed of sheep born in Colorado.
Since then, people from all the around the country have flocked to Colorado’s public lands to catch a glimpse of these once-endangered creatures, along with elk, moose, and other large mammals. Tourists seeking wildlife-viewing opportunities also brought spending money into the state. Today, management strategies have become even more sophisticated, and populations of bighorn sheep are thriving. The recovery of the bighorn sheep population and the success of their management in the state of Colorado helped to solidify the importance of wildlife to the state’s economy.