Colorado State Animal: Rocky Mountain Bighorn Sheep

By the late 1920s, Colorado residents and wildlife officials had watched bighorn sheep decline for decades. Hunters, ranchers, and settlers had pushed the species toward extinction throughout the 1800s. A handful of conservation-minded legislators pushed for the designation partly to raise public awareness. Making the bighorn sheep a state symbol put its survival on the political map.

Colorado's identity is built around its mountains. No other large mammal in the state lives as high, moves as nimbly on steep rock, or represents the alpine wilderness as completely as the bighorn sheep. Elk, mule deer, and mountain lions all share Colorado's mountains, but none of them occupy the extreme terrain that bighorn sheep call home. The legislature chose the animal that lived where no other could.

Colorado is the only state in the contiguous United States where every county seat sits above 5,000 feet elevation. The state's highest point, Mount Elbert, reaches 14,440 feet. Bighorn sheep live in this vertical world more completely than any other large mammal. They embody what it means to thrive where the air is thin, the ground is steep, and conditions punish anything that is not built to survive them.

The Ute people lived in Colorado's mountains for centuries before European contact. Bighorn sheep were important prey for Ute hunters, who tracked herds across high-altitude ridgelines. The Arapaho, who moved into Colorado's eastern plains and foothills, also hunted bighorn sheep during seasonal migrations to higher ground. These hunts required knowledge of the sheep's behavior on steep terrain—a skill developed over generations of living in the Rockies.

Commercial hunters in the 1800s devastated bighorn sheep populations across the West. In Colorado, settlers also converted mountain meadows to livestock grazing. Domestic sheep brought diseases—particularly a form of pneumonia caused by bacteria like Pasteurella and Mycoplasma—that killed wild bighorn populations in waves. By 1900, fewer than 2,500 bighorn sheep remained across all of Colorado. Several mountain ranges had lost their herds entirely.

Colorado's bighorn sheep recovery began in earnest during the 1940s and 1950s. Wildlife biologists developed capture and translocation techniques, moving sheep from healthy herds into areas where they had disappeared. Rocky Mountain National Park became a key source of animals for these programs. Over decades, herds reappeared in mountain ranges across the state. Today, Colorado Parks and Wildlife manages one of the most successful bighorn sheep programs in North America.

Domestic sheep still graze on Colorado's public lands, and the risk of disease transmission to wild bighorn sheep has not gone away. When domestic and wild herds come into contact, pneumonia can sweep through a bighorn population and kill most of a herd within weeks. Wildlife managers spend significant time and effort separating the two populations. The bighorn sheep's survival in Colorado depends on keeping this boundary clear.

Colorado Parks and Wildlife runs one of the most active bighorn sheep management programs in the country. Biologists monitor herd sizes, track disease, and relocate sheep into suitable habitat when opportunities arise. Limited regulated hunting exists in some units—carefully managed to ensure populations remain healthy. The department also works with ranchers and federal land managers to reduce contact between domestic sheep and wild herds on public grazing lands.

Pneumonia transmitted by domestic sheep remains the most dangerous ongoing threat. A single disease event can kill 80 to 90 percent of a wild herd. Habitat fragmentation from roads, subdivisions, and ski resorts also limits the sheep's ability to move between mountain ranges. Climate change is gradually shifting the alpine vegetation that bighorn sheep depend on for food, though scientists are still studying how significant this effect will become over coming decades.

Colorado's state flower, the Rocky Mountain columbine (designated 1899), grows in alpine meadows at elevations up to 11,000 feet. Bighorn sheep graze on and near the same mountain slopes where columbines bloom each summer. Both symbols were chosen because they thrive in terrain that defines Colorado more than any other state. The columbine is the plant of the peaks; the bighorn sheep is the animal of the peaks.

Colorado's state tree, the Colorado blue spruce (designated 1925), grows across mountain elevations from 5,000 to 11,000 feet. Its silvery-blue needles are adapted to survive harsh winters, strong winds, and intense ultraviolet radiation at altitude. Bighorn sheep shelter in spruce-covered ridgelines during the coldest months. Both symbols represent species that evolved to endure conditions most organisms cannot tolerate.

Colorado's state bird, the lark bunting (designated 1931—the same year as the bighorn sheep), lives primarily on the eastern plains rather than in the mountains. The two symbols chosen in the same year represent opposite halves of Colorado. The bighorn sheep belongs to the Rockies. The lark bunting belongs to the grasslands east of Denver. Together they acknowledge that Colorado is not only a mountain state—it is also a plains state.

Colorado earned the nickname 'The Centennial State' when it joined the Union on August 1, 1876—exactly 100 years after the Declaration of Independence was signed. The bighorn sheep had already been a symbol of the Rocky Mountains long before statehood. When Colorado formalized the designation in 1931, it connected an ancient mountain species to a state that was itself relatively young. The sheep predated the state by millennia.