The Bighorn Sheep (Ovis candensis) is remarkable for its ability to survive in conditions as diverse as the snow-capped alplands of the Canadian Rockies and the hot deserts of Death Valley and northern Mexico.
On this page:
- Description of Bighorn sheep
- Distribution and abundance in B.C.
- Population management of Bighorn Sheep
The bighorn’s name comes from the adult male sheep's (ram) massive, brown, spiralled horns that curl back and down close to the head, with tips that project forward and outward just below the eyes. California and Rocky Mountain bighorns look similar, but the California race is slightly darker in colour, and its rams have horns that flare outward more than those of Rocky Mountain rams.
The horns continue to grow throughout the sheep’s life, but growth slows down in winter. This causes rings (or annuli) on the horns; the number of lines indicate the ram’s age. Ram horns can be as long as 127 cm around the curve and as thick as 40 cm around the base. Rams often wear away (or broom) the first year or two's growth by fighting with other rams or rubbing their horns against rocks. Ewes (female sheep) have slightly curved horns about 30 cm long. Their annuli are too close together to tell their age beyond five or six years.
Adult rams stand about 100 cm high at the shoulder and usually weigh 90 to 135 kg. Ewes are about two-thirds the size of rams. Yearling rams (sheep that are a year old or in its second year) look a lot like ewes, but rams two years old or older have larger horns. Bighorns have concave hooves with rough foot pads that provide good traction on rocky terrain.
Bighorn sheep occupy a diversity of ecosystems ranging from cold and high elevations in the northern portions of the Rocky Mountains, to the hottest and driest regions of the southern portion of the province. In fact, B.C. is home to the:
- Rocky Mountain Bighorn Sheep (Ovis canadensis canadensis) located in the Kawka park region of the province, and
- California Bighorn Sheep (Ovis canadensis californiana) that were used as source herds for wild sheep reintroductions across the US
Rocky Mountain Bighorn Sheep
Rocky Mountain Bighorn Sheep habitat is predominantly comprised of grasslands and early-seral shrub lands along the western flanks of the southern Rocky Mountains, where wind and warmer temperatures result in shallow to zero snow depths (Demarchi et al 2000a).
California Bighorn Sheep
California Bighorn Sheep are slightly smaller than the Rocky Mountain bighorns and are more commonly found in areas with large expanses of open southerly and westerly-facing grassland slopes, parkland forest, canyons, and deep valley walls, east of the Cascade Mountains and west of the Selkirk and Rocky Mountains, from the Chilcotin River in the southern interior of the province to the Sierra Nevada Mountains of California (Demarchi et al 2000b).
Distribution of bighorn sheep in B.C.
The abundance and distribution of bighorn sheep have always been restricted due to their use of specialized wintering habitats and their dependence on rough, precipitous terrain for predator avoidance (Demarchi et al 2000a and 2000b). Our historic abundance is what allowed B.C. between 1954 and the year 2000, to contribute almost 700 sheep to US mid-west states to aid in restoring the range and distribution of bighorns sheep populations in North America.