The desert bighorn sheep (Ovis canadensis nelsoni) is a subspecies of bighorn sheep (Ovis canadensis) that is native to the deserts of the United States' intermountain west and southwestern regions, as well as northwestern Mexico. The Bureau of Land Management considered the subspecies "sensitive" to extinction.
The trinomial of this species commemorates the American naturalist Edward William Nelson (1855–1934). The characteristics and behavior of the desert bighorn sheep generally follow those of other bighorn sheep, except for adaptation to the lack of water in the desert. They can go for extended periods of time without drinking water.
The desert bighorn sheep is the state mammal of Nevada. It is also the mascot of the Universidad Autónoma de Baja California.
The range of the desert bighorn sheep includes habitats in the Mojave Desert, Sonoran Desert, Great Basin Desert, and Chihuahuan Desert, as well as the Colorado Plateau. Anza-Borrego Desert State Park, Joshua Tree National Park, Death Valley National Park, Kofa National Wildlife Refuge, Cabeza Prieta National Wildlife Refuge, Zion National Park, and Mojave National Preserve all offer protected habitat for them. The subspecies is considered extirpated from Oregon.
Populations of the desert bighorn sheep declined drastically with European colonization of the American Southwest beginning in the 16th century. These declines were followed by a period of population stabilization ascribed to conservation measures. As of 2004, desert bighorn sheep numbers remained extremely low, although the overall population trend had increased since 1960.
Desert bighorn sheep are stocky, heavy-bodied sheep, similar in size to mule deer. Weights of mature rams range from 115 to 280 pounds (52 to 127 kg), while ewes are somewhat smaller. Due to their unique concave elastic hooves, bighorn are able to climb the steep, rocky terrain of the desert mountains with speed and agility. They rely on their keen eyesight to detect potential predators, such as mountain lions, coyotes, and bobcats, and they use their climbing ability to escape.