Species: Ovis canadensis

Bighorn Sheep

Species

Encyclopedia of Puget Sound

Upper pelage varies from dark brown to pale tan, with a whitish underside. Tail is short. is tan or reddish brown in summer, grayish brown in winter. Mature male has massive horns that form a C-shaped curl. Horns of adult female are shorter and more slender, forming a half curl at most. Juveniles have a pale, soft, woolly coat and lack horns.

Source: Encyclopedia of Life

Classification

Kingdom

Animalia

Phylum

Craniata

Class

Mammalia

Order

Artiodactyla

Family

Bovidae

Genus

Ovis

NatureServe

Source:
ELEMENT_GLOBAL.2.102557

Classification

Other Global Common Names

Mountain Sheep - mouflon d'Amérique

Informal Taxonomy

Animals, Vertebrates - Mammals - Other Mammals

Formal Taxonomy

Animalia - Craniata - Mammalia - Artiodactyla - Bovidae - Ovis - (Luikart and Allendorf 1996).

Ecology and Life History

Source: Encyclopedia of Life

Short General Description

A large ungulate (sheep).

Migration

false - true - false - Populations other than those in low deserts typically migrate between an alpine or montane summer range and a lower elevation winter range (Shackleton et al. 1999). Some may occupy as many as five separate ranges during a year (Geist 1971). This vertical migration is probably a response to the increasing abundance of nutritious, new vegetative growth at higher elevations as spring and summer progress (Shackleton et al. 1999). The downward migration is motivated by snow accumulation in the high elevation summer ranges (Shackleton et al. 1999).

Non-migrant

false

Locally Migrant

true

Food Comments

Diet is diverse and variable. Bighorn sheep are primarily grazers of grass and forbs, but the diet can also include significant amounts of shrubs (Miller and Gaud 1989, Krausman et al. 1999, Shackleton et al. 1999). Diet changes seasonally. Access to mineral lick may be important for Rocky Mountain and desert bighorns, especially in spring (Shackleton et al. 1999, Krausman et al. 1999).

Reproduction Comments

The timing of the mating season varies throughout the range. Bighorns in southwestern deserts have an extended season encompassing several months (Krausman et al. 1999), but the season is relatively later and shorter elsewhere, generally November in the northern part of the range (Shackleton et al. 1999), November-December in some southern California mountains (DeForge (1980). Gestation lasts about 175 days (Geist 1971, Shackleton et al. 1999). Lambing generally peaks in March in desert populations (Rubin et al. 2000), May (occasionally April or June) in the remainder of range (Krausman et al. 1999, Shackleton et al. 1999). Litter size is 1, rarely 2 (Geist 1971, Turner and Hansen 1980).Young are weaned in 4-6 months. Females first breed usually in second year in south, third year in north; occasionally in first year in some areas (Krausman et al. 1999, Shackleton et al. 1999); fecundity generally declines only slightly after eight years of age (Caughley 1977). In the mating season, mature males battle over access to females through vigorous head butting contests, but during most of the rest of the year they live amiably in small bands apart from the females.

Ecology Comments

Gregarious, but for most of the year adult males live apart from females/young (Shackleton et al. 1999, Krausman et al. 1999). Among mature males, older males (up to an age of not more than 10 years) generally dominate younger males during the breeding season; males older than 10 years decline rapidly in condition. In western Arizona, January-June home range of adult females was 19-27 sq km (Seegmiller and Ohmart 1981). Male annual home range up to 37 sq km in Nevada (Leslie and Douglas 1979). Carrying capacity for bighorn can be reduced through grazing by other ungulates (cattle, burros, etc.). In the Santa Catalina Mountains of southern Arizona, not limited by forage quantity or quality (Mazaika et al. 1992). Contact with a stray domestic sheep is believed to have resulted in the death (through bacterial pneumonia) of entire reintroduced herd of 65 in Warner Mountains, California (California Department of Fish and Game 1990). In some areas, lungworm infections may predispose bighorn to respiratory infection by opportunistic bacteria; lungworm life cycle involves gastropod intermediate host. In desert, can survive 10 or more days in summer without drinking; may meet water needs in part by eating barrel cacti (Warrick and Krausman 1989). PREDATION: Probably live in groups primarily to reduce predation (Shackleton et al. 1999). Coyotes may be a significant predator on young in some areas, killing up to 80% of the year's lambs (Hebert and Harrison 1988, Harper 1984, Hass 1989). Cougars can be important predators as well (Harrison and Hebert 1988, Krausman et al. 1999), and can have significant impacts on remnant or transplant herds (Krausman et al. 1999). Direct losses to predation are not generally as important as the fact that predation has forced females and young to use less productive habitats in and near escape terrain (Festa-Bianchet 1988, Demarchi et al. 1999a).

Length

185

Weight

150000

Conservation Status

NatureServe Global Status Rank

Global Status Last Reviewed

2008-10-06

Global Status Last Changed

2000-11-30

Distribution

Conservation Status Map

Global Range

H - >2,500,000 square km (greater than 1,000,000 square miles) - H - Range includes mountains and river breaks from southwestern Canada (southern British Columbia and southwestern Alberta) south through the Rocky Mountains, Sierra Nevada, and desert mountains of the southwestern United States to Baja California and the northwestern mainland of Mexico. Distribution is naturally fragmented in many areas due to discontinuity of habitat. Local extirpations and subsequent reintroductions from local or distant stocks have occurred in many parts of the range. For example, this species formerly ranged east to the badlands in western North Dakota and Black Hills of South Dakota; after extirpation there, individuals from non-native populations were introduced (Valdez and Krausman 1999).

Global Range Code

Global Range Description

>2,500,000 square km (greater than 1,000,000 square miles)

ELEMENT_GLOBAL.2.102557