Scientific Classification of North American Wild Sheep:
Kingdom: Animalia
Phylum: Chordata
Class: Mammalia
Order: Artiodactyla
Family: Bovidae
Genus: Ovis
ROCKY MOUNTAIN BIGHORN
STONE SHEEP
DESERT BIGHORN
DALL SHEEP
BIGHORN SHEEP OR MOUNTAIN GOAT?
CONSERVATION EFFORTS
Rocky Mountain Bighorn
Ovis canadensis canadensis
The Rocky Mountain Bighorn Sheep is the largest wild sheep inhabiting North America. A large ram (a male sheep) may weigh over 300 pounds and stand over 42 inches tall at the shoulder. They are generally a dark brown to gray/brown color with a white rump patch, muzzle, and back of legs. Their coats may appear considerably lighter in spring before the winter coat is shed, revealing the darker summer coat beneath. Rams have horns that are massive and tightly curled close to the face. A ewe (a female sheep) will have smaller, shorter horns that curve only slightly. Ewes typically weigh 125-150 pounds. Rocky Mountain Bighorns are found in British Columbia; Alberta, Canada; and in the western United States as far south as New Mexico.
Desert Bighorn
Ovis canadensis nelsoni
Desert Bighorn Sheep are generally smaller and lighter colored than their cousins, the Rocky Mountain Bighorn Sheep. Large rams usually weigh under 220 pounds. They stand 38-42 inches tall at the shoulder. Desert Bighorns are found in the southwestern United States, including Utah, Nevada, New Mexico, Arizona, and southern California. A significant population is also found in northern Mexico. The horns of Desert Bighorns are typically longer and not as massive as those of Rocky Mountain Bighorns. These horns are usually curled close to the face but may flare widely outward, showing wide variation in horn structure between individuals. Desert Bighorns also have slightly longer ears and tails than Rocky Mountain Bighorns. Desert Bighorn ewes also typically have longer horns than other North American wild sheep females.
Dall Sheep
Ovis dalli dalli
The most striking feature of the Dall Sheep is their nearly all white color. The Dall Sheep is actually a “thinhorn” sheep. Their horns are longer, thinner, and yellower in color when compared to horns of Bighorn Sheep. Their horns also tend to flare outward, away from the face. Ewes’ horns are usually under 12 inches long. Dall rams can weigh 225 pounds and stand 40 inches tall at the shoulder. Dall Sheep primarily inhabit Alaska and the Yukon Territory but are also found in British Columbia and the Northwest Territories.
Stone Sheep
Ovis dalli stonei
The Stone Sheep is another “thinhorn” sheep and a darker subspecies of the Dall Sheep. Stone Sheep rams can weigh up to 250 pounds and stand 40 inches tall at the shoulder. Ewes typically weigh 30-40% less than the rams and stand 36 inches tall at the shoulder. There are many color phases of Stone Sheep, from an almost-black charcoal to a light grey/brown and “salt and pepper.” They typically have lighter faces, a white rump patch, and white on the backs of their legs. Their horns are longer, thinner, and yellower than those of bighorns and tend to flare outward, away from the face like those of Dall Sheep. Stone Sheep are primarily found in southern Yukon Territory and northern British Columbia. In areas where the ranges of Stone Sheep and Dall Sheep may overlap, an intermediate color phase may be found, which is referred to as a “Fannin’s Sheep.” Technically, an otherwise white sheep with black hairs anywhere except on the tail is considered a Stone or Fannin’s Sheep.
Bighorn Sheep or Mountain Goat?
Oreamnos americanus
The Mountain Goat, Oreamnos americanus, is often confused with white wild sheep. Wild sheep and mountain goats (Oreamnos americanus) are close cousins, both belonging to the Family Bovidae, but they are distinctly different species. To the inexperienced eye, female sheep, especially Dall sheep, may be confused with mountain goats. The most obvious differences between wild sheep and goats are hair color, horn color and structure, and hair length. Mountain goats are creamy-white or yellowish-white, never tan, brown, or grey. Both sexes of goats have black horns. When compared to the horns of sheep, mountain goats’ horns are thinner, sharper, and swept backward, not curling.
Goats horns average 10″ in length. Mountain goats also have longer hair than wild sheep. Especially in winter, the longer hair may form a beard under the chin, and the abruptly ending longer hair on the front legs gives them the appearance of wearing “pantaloons.” Goats also have longer, thinner, and sharper ears, often described as “pixie-like.” Billies (male goats) can reach over 250 pounds, and a large nanny (female goat) may weigh 200 pounds.
The ranges of mountain goats and wild sheep may overlap, but goats will usually choose terrain that is even steeper and more precipitous than terrain favored by sheep. When feeding and bedding areas are challenged, goats will usually become more aggressive than sheep and push sheep out of contested territory. Mountain goats are found in Canada, Alaska, Washington, Idaho, Oregon, and Montana. Small populations found in other states, including Wyoming, exist because of transplantation.
Bighorn Sheep Challenges and Conservation Efforts
Bighorn Sheep throughout North America, including our local Whiskey Mountain herd, struggle with habitat difficulties, diseases, and other challenges. The National Bighorn Sheep Center works with our partners to educate the public about these and other threats to bighorns and current conservation efforts conserving wild sheep populations.
Disease research, population monitoring, habitat enhancement projects, wild sheep relocation, and efforts to reduce wild and domestic sheep interactions: Our partners employ all these strategies and more to ensure that wild sheep populations are better understood, managed, and conserved. Our work in education at the Center, in classrooms, and in the field helps connect people to these opportunities and learn about what can be done to help wild sheep populations now and in the future.
Whiskey Basin Collaborative Project
WHISKEY MOUNTAIN BIGHORN SHEEP UNDERSTANDING AND SOLUTIONS THROUGH COLLABORATION
In early 2019, the Wyoming Game and Fish Department (WGFD), in partnership with the Wyoming Wild Sheep Foundation, the National Bighorn Sheep Center, and the University of Wyoming’s Ruckelshaus Institute, engaged in a public involvement process to explore management concerns, issues, and opportunities for the Whiskey Mountain Bighorn Sheep herd. The Whiskey Mountain bighorn sheep herd was once one of the largest and most nationally recognized herds in the nation, and it has been declining since an all-age die-off in the early 1990s. The herd continues to stay below the desired population size primarily because lamb survival is very low. At one time, there were an estimated 2,500 sheep in this population; today, there are about 750.
WHY DO THIS?
The Wyoming Game and Fish Department simply doesn’t have all the answers to turn this important bighorn sheep population around. There is much to be learned about how best to address this decline and perhaps implement new or different management strategies and projects to attempt to arrest and reverse this trend. To do this, we must consider a different approach that includes all who are interested in and passionate about this herd.
Additionally, in 2019, NBSC began exploring Citizen Science Data Collection as one way for the public to get involved and help with the observations of bighorn sheep in the Whiskey Basin area. The University of Wyoming has provided the basic data collection form in the bottom link below, and the public is encouraged to help provide observational data through this form to the University.
LINKS:
For a link to the full Situational Assessment, released on December 19, 2018, please click here: Whiskey Mountain Situation Assessment Final
For a link to the full notes from the first February 2019 meeting, please click here: Whiskey Mountain BHS Workshop 1 Notes Final
For links to the April 2019 workshop agenda, professionals’ input and issues summary from the February meeting click here:
Final Agenda Workshop 2
WMBHS Scientists Recommendations
WMBHS Issues Spreadsheet Final
For a link to the Citizen Science Observation Form, click here: CitizenScienceDataSheet
Read the DRAFT Whiskey Mountain Bighorn Sheep Plan in the final link below.
The updated management plan as of July 17, 2019. Read it Here: