Bighorn Sheep have big horns indeed. They are bigger compared to Dall’s and Snow Sheep. But the Bighorn does not hold the record for the longest horns.

Names

English: Bighorn Sheep, Mountain Sheep [6, 16]

French: Mouflon D’Amérique [6, 16], Mouflon Du Canada, Mouflon Pachycère [6]

German: Dickhornschaf [7, 16]

Spanish, Castilian: Carnero de las Rocosas [16], Borrego Cimarrón, Carnero Del Canadá, Carnero Salvaje [6]

Taxonomy

Ovis canadensis Shaw, 1804, Alberta, Canada

diploid chromosome number: 54 [16]

Bighorn Sheep (Ovis canadensis) are most closely related to Sibirian Snow Sheep (Ovis nivicola) and Dall’s Sheep (Ovis dalli). The three species are summarized as Mountain Sheep (german: Bergschafe). Mountain Sheep differ from Eurasian wild sheep substantially in physical appearance and survival strategy. In absence of true goats (Capra) they evolved into short-legged, compact climbers in contrast to the long-legged runnertyps from Asia. In short: Mountain Sheep, including Bighorns, inhabit the ibex-niche. [5]

North American Mountain Sheep reached the continent form Asia during the Middle-Pleistocene. [5] Bighorn and Dall’s Sheep probably hybridized prior to glacial maxima and during late Pleistocene in ice-free refugia. [16].

Subspecies

Many scientists currently recognise three Bighorn subspecies:

Rocky Mountain Bighorn Sheep (Ovis canadensis canadensis)

Sierra Nevada Bighorn Sheep (Ovis canadensis sierrae)

Desert Bighorn Sheep (Ovis canadensis nelsoni) [1, 2]

The seven subspecies of Bighorn Sheep proposed by Cowan (1940) have come under taxonomic scrutiny. Genetic data (Ramey 1993, 1995; Boyce et al. 1997; Gutierrez-Espeleta et al. 1998) and morphological data (Wehausen and Ramey 1993, 2000) do not support Cowan’s original subspecies distinctions. [2] And it is still questioned if there are any subspecies at all. [4]

As a result of morphometrical measurements, protein and mtDNA analysis, Ramey (1991, 1993, 1995) recommended that of the four subspecies of Desert Bighorn Sheep, only a single subspecies – O. c. nelsoni – be recognized. Ramey (1999) also suggested that California and Rocky Mountain subspecies be combined into one subspecies (O. c. canadensis). Wehausen and Ramey (2000) revised the taxonomy of North American mountain sheep and designated the animals in the Sierra Nevada as O. c. californiana – the only representative of that taxon. Grinnell (1912) had assigned the subspecific epithet sierrae to animals from the Sierra Nevada and as it has been affirmed that sheep in the Sierra Nevada warrant subspecific recognition, judicious application of the rule of priority dictates they are again assigned to the subspecies sierrae (Wehausen et al. 2005). That nomenclature change ended the subspecies O. c. californiana. At the same time, all other wild sheep formerly designated as californiana were synoymized with O. C. canadensis or O. c. nelsoni. [2]

However, there may be room in future for a fourth Bighorn Sheep subspecies. The bighorned sheep from western British Columbia, which were formerly misnamed California Bighorn Sheep, and are „nowhere near“ ((editor’s note: This must be a misspelling. It should be „now near“)) to meeting the criteria for subspecies status, offer a few hints (e. g. morphometric differences) that they have drifted somewhat from the Bighorns in the Rocky Mountains. These particular sheep may be associated with a glacial refugium from which the Canadian Rockies were recolonized after glacial retreat. There are, however, uncertainties with both their defined geographical range, especially with the introduction of these sheep into many areas outside the natural distribution range (e. g. into the historic habitat of Rocky Mountain and Desert Bighorn Sheep) and also with the Bighorn management philosophies in some US jurisdictions. Further research into morphometric and molecular aspects is necessary. Discussion about an appropriate vernacular name, which refers perhaps to the historic geographic region of distribution (Williams Lake, for example, since so many translocated populations originate from this area), is the other prerequisite before coming to a final conclusion. [2]

Table 1: Bighorn Sheep subspecies – current and former

Rocky Mountain Bighorn Sheep (Ovis canadensis canadensis)

 

Rocky Mountain Bighorn (Ovis c. canadensis)

Audubon’s Bighorn (O. c. auduboni)

California Bighorn (O. c. californiana)*

Sierra Nevada Bighorn Sheep (Ovis canadensis sierrae)**

 

California Bighorn (O. c. californiana)*

Sierra Nevada Bighorn (Ovis c. sierrae)

 

Desert Bighorn Sheep (Ovis canadensis nelsoni)

 

Mexican Bighorn (O. c. mexicana)

Peninsular Bighorn (O. c. cremnobates)

Nelson’s Bighorn (O. c. nelsoni)

Weems‘ Bighorn (O. c. weemsi)

* California Bighorn (O. c. californiana) have been synonymized with both canadensis and nelsoni.

** Populations formerly assigned to californiana in the central and southern Sierra Nevada of California have been assigned to sierrae. [16]

Distinctions between subspecies: Geist (1971) noted that more southerly populations from lower altitudes and poorer forage may be expected to be smaller than the more northerly, high altitude and cold adapted populations living in seasonally abundant forage habitats. [2] Northerly Bighorns have also long awn hairs and a dense undercoat, while Desert Bighorns have short hair. Former have small, thick-haired ears, while the latter have longer ears. [5]

Similar species

The Dall’s Sheep (Ovis dalli dalli) has a pure white or creamy white coat. The Stone’s Sheep (Ovis dalli stonei) is variable in pelage colour and is not as heavy as the Bighorn. The Snow Sheep (Ovis nivicola) from Siberia has lighter horns [1] and its white rump patch is clearly defined below the base of tail [16], whereas in the Bighorn the rump patch surrounds the tail [1]. Some southern Bighorns are as small as Dall’s Sheep, although they have kept their heavier horns and bigger molars. In general Bighorns have bigger horns compared to Dall’s and Snow Sheep [5]. But the longest recorded horn of any North American wild sheep belongs to a Stone’s Sheep specimen. [2]

Distribution

by country: Canada (West), United States (West), Mexico (North) [6]

In Canada, the Bighorn Sheep (O. c. canadensis) is distributed throughout the Rocky Mountains in Alberta and British Columbia, south from the Peace River to the Canada-USA border. Two small populations also have been introduced to central British Columbia outside their normal distribution.

Populations of the putative California Bighorn Sheep subspecies (see notes above) are scattered through central British Columbia from north of Anahim Lake, south along sections of the Chilcotin, Chilco and other western tributaries of the Fraser River south of William’s Lake and west to just north of Lillooet, and also south from around Kamloops along both sides of the Okanagan Valley to the border with Washington State (USA) and as far west as Granby, British Columbia. Populations around Kamloops and Granby have been introduced, mostly into historically occupied habitat. [6]

In the United States, the Bighorn Sheep is widely distributed from Montana and Idaho south through Wyoming and northern Utah, to Colorado and New Mexico. These Bighorn herds comprise most of the traditional O. c. canadensis for which Thorne et al. (1985) estimated a population of greater than 19.000. [6]. The Sierra Nevada Bighorn (O. c. sierrae) occurs in a relatively small area in the Sierra Nevada, California. [2]

To the west, Bighorn occur in scattered populations in the Columbia Plateau and Great Basin ranges of Washington, Oregon, southwest Idaho, and northern Nevada. These herds comprise most of the traditional O. c. californiana, for which Thorne et al. (1985) estimated greater than 2.800 animals. East of the Rocky Mountains, Bighorn exist in scattered herds in badlands and river-breaks in eastern Montana, North and South Dakota, northeast Wyoming, Nebraska, and outside of historic range in southeast Colorado. [6]

To the south, Desert Bighorn (O. c. nelsoni) inhabit southern portions of California, Nevada, Utah and New Mexico, much of Arizona, and west Texas. Weaver (1985) estimated 16.000 Desert Bighorn in this area. However, there are few Bighorn and few herds (mostly transplants to reintroduce Bighorns in areas where they were extirpated) within the Chihuahuan Desert of New Mexico and west Texas. [6]

In Mexico, Bighorn Sheep were restricted to three states for quite some time: Northwestern Sonora, Baja California and Baja California Sur. [6] They now occur also in Chihuahua, Coahuila, Nuevo Leon, Sonora, and on Tiburon Island in the Sea of Cortez [2]

Description

general appearance: Bighorn Sheep – and especially Rocky Mountain Bighorns – are generally blocky animals with heavy compact bodies, relatively short and powerful legs, muscular front and hindquarters, sturdy necks and backs. Desert Bighorns have a more slender build. [2] Males can be up to 70 per cent larger than females. [16]

body length: 109-169 cm (males); 96-126 cm (females) [16]

shoulder height: 81-112 cm (males); 76-91 cm (females) [16]

weight: means 79 kg (males) – up to 145 kg; means 59 kg (females) – up to 104 kg [16]

average scull weights: Rocky Mountain Bighorn 11,3 kg; Desert Bighorn 7,5 kg [10]

tail: 10,2-15,2 cm (males); 10,2-12,7 cm (females) [16]

Colouration / pelage

pelage in general: Body colour is pale brown to dark chocolate, including the tail. [16] In general animals from northern populations are darker than those of more southerly areas. [7]

summer coat: lighter [7]

winter coat: darker than during spring or the warmer months; males can appear darker than females [7]

muzzle: white [7, 16]

neck ruff: non-existent [16], but neck hair is longer during winter [7]

tail: short, dark-brown or black [7]

mitdorsal line: blackish-brown, extending to the tip of the tail [2]

rump patch: distinct, white; extends to the side of the rump and above the base of the tail and continuous with the hind legs [16]

belly: white [16]

scrotum: white [7]

legs: posterior (back) side white [16]

pelage of juveniles: like the ewes [7]

pelage of neonates: grey [7]

Horns

The longer, more massive curling horns of males clearly differentiate males and females [16]. Horn weight can reach up to 13 per cent of the body weight. [7] The mass of male sculls with horns minus lower jaw can exceed 20 kg. [16]

Horn growth begins with 2 months and takes place during the warmer months of the year. With 5 and a half months horn length is 5 to 7 cm. After 12 months horn lenghts of males and females remain the same, but basal circumference is more distinct in males. Growth segments are clearly defined by annuli. During the second year length growth is most pronounced. Until the third or fourth year each year the increment is several centimetres. With the seventh or eighth year growth rings measure only millimetres. Shackleton (1985) mentions that age determination in females is difficult after their fifth year. [7] Horns are often broken. Such breakage is caused by fighting, as Shackleton and Hutton (1971) have shown. [10]

horn length, males: means 90 cm – up to 126 cm [16]

horn length, females: means 26,2 cm [16]

horn circumference, males: means 37,3 cm – up to 44 cm [16]

horn circumference, females: means 12,8 cm [16]

Habitat

Habitats include rough to gentle slope in mountains and foothills, talus cliffs, rock outcrops, mesa tops, and canyons and adjacent river benches. Steep, rugged terrain used for escape or security cover is a major habitat component, especially for ewes with lambs. [16]

Bighorn Sheep are found at elevations from below sea level in Death Valley, California, to above 3.500 metres. [16]

Temperatures can vary from -40°C in northern regions and higher elevations to greater than 40°C in desert habitats. [16]

Habitats encompass a variety of plant communities, including grasslands, alpine and subalpine meadows, riparian zones, shrub-steppes, desert, clear-cut or burned tall vegetation, and deciduous and conifer forests. Bighorn Sheep usually avoid areas with tall vegetation that obstructs their vision. Northern populations require grazing areas devoid of deep snow, such as wind-blown sites. In desert areas, water availability is an important factor, but sheep can survive without standing water for long periods [16]. They also take in snow. [7]

Food and feeding

Diets are highly variable due to the wide geographic landscape and habitat variability, seasonal availability of forage species, and potential age and gender forage preference differences. [16] Bighorns mostly eat grass, but they also consume forbs and browse. [6] In desert areas, shrubs can comprise more than 90 per cent of summer diets. Water and seasonal precipitation have important effects on forage availability, quality, and palatability, especially in desert environments, and largely determine diet composition. Mineral licks are important sources of sodium, phosphorus, calcium, and probably trace minerals. [16]

Mortality / predators

Major predators include Coyotes (Canis latrans), Gray Wolves (Canis lupus), Pumas (Puma concolor), and other carnivores like Bobcats (Lynx rufus) [16] and Lynx (Lynx canadensis) and Wolverines (Gulo gulo) [7]. Golden Eagles (Aquila chrysaetos) are also a factor. Puma predation by individuals that concentrate on sheep can depress population growth in some instances. [16]

In one study Bighorn Sheep predation by Puma reached 13 per cent of the population in November alone and 57 per cent of the total winter mortality. Of 29 killed Bighorns 13 were lambs and 7,9 animals were between 1 and 17 years of age. Predation by Puma according to Ross et al. (1997) appears to be individually learnt. [7]

Lamb and yearling mortality is highly variable, 20 to 80 per cent for lambs and 5 to 30 per cent for yearlings, and can exceed 90 per cent during disease outbreaks, exceptionally cold, wet weather, or droughts. Coyotes and Bobcats are important predators of lambs. [16]

Breeding

Females are monestrous (experiencing estrus once a year). Males are serially polygynous. [16]

sexual maturity: females at 18 months [6]; ewes usually first mate when 2,5 years old and first give birth when three years old. Males are mature by 1,5 years, but usually they are prevented from participating in the rut by older rams. Males older than five years do most of the breeding. [16] Growth of testicles starts to increase 2 to 3 months prior to rutting season, they reach 12 times 6 centimetres. [7]

rutting season: in northern populations in late November and early December; in desert environments, mating season is prolonged [16]

rutting behaviour: Dominant, larger bodied, longer-horned rams guard a single estrous ewe from other rams. Dominance among rams is established by ritualised head and body displays and by physical interactions, including horn clashes and head butting [16]. Most spectacular is when males clash their heads. When they run towards each other, front limbs typically don’t touch the ground. While running the rivals may reach 32 km/h, and the impact might be heard at a distance of one kilometre away. [7]

social rank in ewes: not correlated with reproductive success, but high-quality females, those in a high nutritional plane, have a consistently higher probability of reproduction [16]

gestation: 175 days [6], 170-180 days [16]

lambing season: late May and early June; in desert environments births occur from January through June, probably due to unpredictable precipitation patterns, although there is usually a peak period in births. [16]

parturition timing: coincides in northern populations with warmer temperatures and the growth of spring vegetation; in desert environments the peak birth period coincides with a predictable timing of the winter-spring forage growing season, indicating that most desert sheep births also coincide with the period of nutrient availability [16]

birth sites: rugged, steep terrain in seclusion [16]

number of young: one [6, 16], twins are rare [16]

lamb weight: 2,7 to 4,5 kg [16]

lamb and ewe behaviour: After one or three days, when the lamb is able to follow the mother, they join a ewe herd. Lactating ewes are more vigilant about predators than non-lactating ewes. [16]

lamb survival: greater in ewes aged 4-12 years than for ewes aged 2 or 3 years [16]

 

Longvity: Very few females live more than 15 years in the wild [6], but some are known to have lived up to 19 years. [16] Very few males survive past 12 years, [6] although some attained 14 years in the wild [16]. In captivity one Desert Bighorn ram died with 16 years and 8 months, and one ewe with 20 years and 7 months (Weigl 2005) [7].

Activity pattern

The harder life is, the more active the animals are: During warm weather, feeding activities are concentrated at dusk and dawn. During winter, feeding periods increase, probably influenced by the shortened daylight hours and the poorer nutritional quality and availability of forage plants, especially in deserts and northern areas with snow cover. In deserts, feeding activity is curtailed by high summer temperature during the day. Females, because of their added nutritional demand during pregnancy and after lambing, can spend proportionately more time feeding than males. Smaller rams spend more time foraging than larger rams. [16]

Movements, home ranges and social organisation

Movements – now and then: Northern Bighorn Sheep usually migrate seasonally between winter and summer home ranges, which can involve movements of 10 to 20 kilometres. Female herds show high home range fidelity. Elevational migrations are evident in northern populations in relation to plant phenology and to avoid areas of snow accumulation. Desert population movements are related to seasonal water and forage availability. Males tend to make longer movements and have much larger home ranges than females, especially during the mating season. They can move 50 to 60 kilometres and encompass several mountain ranges. In the pre-Columbian period, when human structures were not a hindrance, desert populations were not sedentary, and the sheep crossed lower-elevation intermountain regions to move between mountain ranges. [16]

Sex, water, forage: decisive for home range sizes. In Utah, the mean home range size for males was 61 km²; for females it was 24 km². In arid areas, large female home ranges were correlated with widely scattered water sources; during the rainy season, home ranges and movements can increase because of greater availability of watering sources. However, in western Arizona, home ranges decreased with increasing precipitation indicating that forage quality was related to home range area. [16]

More eyes see more – and more: Bighorn Sheep aggregate in herds, which increases feeding efficiency and predator avoidance. Herd size, which can vary from 2 to over 100 individuals, is dependent on population size, habitat availability, season, and gender. During an extended period of the year, males form separate groups from females and occupy separate seasonal home ranges, but there can be spatial and temporal overlap. [16] For males group sizes usually range from 5 to 50; nursery groups of females, lambs and young males encompass 5 to 100 individuals. [6]

Ewes go for security and water, rams for feed quality: Females select for areas with higher security cover (steep, rugged terrain) to maximize lamb survival, even though these areas can have lower forage quality. [16] Females also select areas with better water availability. It is assumed that water is associated with milk production. [7] Males select for higher forage quality or quantity to maximize body condition, at the risk of higher predation vulnerability. [16]

Female or maternal herds are composed of adult females, subadult females, lambs, and juvenile males. Young males leave female herds when they are old enough to dominate females, as 2-3-year-olds. Subadult males tend to rejoin female herds in summer. Young females remain within their maternal herds throughout their life. [16]

Mature males join ewe herds during the mating season, which increases herd size and probably stimulates sexual behaviour and synchronises estrous among females. Single males may be more evident during the mating period because of their movements in search of estrous ewes. Males form dominance hierarchies, with older, larger males dominant over younger, smaller males. Dominance is correlated with reproductive fitness. Older, physically and socially mature males do most of the mating, but in some populations, subadult rams can sire equal numbers of lambs. [16]

Status

IUCN classifies the species Ovis canadensis as „least concern“. Date assessed: 30 June 2008 [6]

By the early 1900s, many populations had been extirpated. Populations have been reestablished in al states where they had become extinct and even introduced in areas where they did not occur historically; introductions often have been from individuals that were not of the original genetic stock.

Canada: The total population of all Bighorn Sheep in this country is estimated to be ca. 15.500 to 15.700 individuals. Of this total, ca. 11.500 to 11.700 are estimated to be Rocky Mountain Bighorns [Alberta 10.300 (K. Smith, in litt., 1994), and British Columbia 1.500 to 1.700 (Hebert et al., 1985)], and ca. 4.000 Bighorn – which were formerly treated as California Bighorn – whose individual populations range in size from 15 to 2.400 animals. Most populations of both subspecies are either increasing or stable. [6]

United States: In 1990, Bighorn Sheep were estimated to be greater than 42.700 individuals in over 340 recognized herds, in 14 of the states. However, 64 per cent of the herds had less than 100 animals (Thorne et al., 1985; U. S. Bureau of Land Management, n.d.), but most of these populations have since increased. [6]

Mexico: In 2014 the total number of Desert Bighorn Sheep in Mexico probably approached 10.000 animals. [2] This is a great success story considering that in 1992 the total estimate was just around 4.500 animals. [6]

Threats

Historically epizootics have occurred periodically, especially in Rocky Mountain Bighorn, and together with over-harvesting and competition from livestock at the end of the 19th century and beginning of the 20th, reduced numbers significantly. Most populations recovered with the aid of wildlife management and conservation efforts. [6]

Today pneumonia and mange epizootics still occur, particularly in populations that come into contact with domestic sheep and goats. [6] Translocations have been more successful when domestic sheep are not closer than 6 kilometres of known Bighorn used areas. [16]

Bighorn Sheep partially occur in habitats that are not uniformly distributed and that are increasingly being fragmented, making it impossible for groups to interact and interbreed. [16] Especially in the United States many herds are small (< 100). [6]

Other problems include habitat loss due to urban expansion, including oil, gas, and mineral exploration and exploitation. [16]

Poaching of large trophy males is a problem in many areas, including within national parks. [6]

Exotic ungulates (e.g. Aoudad [7] and Persian Wild Goats [5]) can compete for forage and space, and exotics, together with domestic livestock, can transmit diseases. [16]

In Mexico the threats are poaching, competition from domestic livestock, and habitat degradation (Sandoval, 1985). [6]

Inbreeding of different Bighorn subspecies after translocations has been a concern. [12] After simplifying the subspecies status this is probably less of a concern today.

Conservation

In Canada, more than 4.500 Rocky Mountain Bighorns are fully protected within five National Parks (Banff, Jasper, Kootenay, Waterton, Yoho). An even larger number receive some level of protection in provincial parks and other protected areas in Alberta and British Columbia. Animals in protected areas are often especially vulnerable to poaching because they are habituated to humans and are also readily accessible. [6]

Outside national parks, both subspecies of Bighorn sheep are covered by provincial or state wildlife acts, and many populations can be hunted under license (see below). [6]

In the United States, Bighorn Sheep occur in the following 30 National Parks, Monuments, Recreation Areas and Wildlife Refuges:

Arizona: Grand Canyon NP; Cabeza Prieta, Havasu, and Kofa WRs; Glen Canyon, and Lake Mead NRAs; Organ Pipe Cactus NM;

California: Sequoia-Kings Canyon NP; Death Valley, and Joshua Tree NMs;

It also occurs in the large Anza-Borrego State Park (California).

Colorado: Mesa Verde, and Rocky Mountain NPs; Colorado, and Dinosaur NMs;

Montana: Glacier, and Yellowstone NPs; Bison Range, and C.M. Russell NWRs; Bighorn Canyon NRA;

Nevada: Desert NWR; Death Valley NM; Lake Mead NRA;

New Mexico: San Andres NWR; North Dakota: T. Roosevelt NP; Oregon: Hart Mountain NWR;

South Dakota: Badlands NP;

Utah: Arches, Canyonlands, Capitol Reef, and Zion NPs; Dinosaur NM; Flaming Gorge, and Glen Canyon NRAs;

Wyoming: Grand Teton, and Yellowstone NPs; Bighorn Canyon NRA.

Most of these protected areas are in the Mojave and Sonoran deserts, and on the Colorado plateau. Numerous other federal lands administered by the Forest Service and Bureau of Land Management also contain Bighorn. [6]

Return of the Bighorn: Fourteen state wildlife agencies have transplanted sheep onto more than 200 historic ranges. This has accounted for much of the recovery of Bighorn Sheep from historic low numbers in the 1960s. However, numerous other transplants have failed (Bailey, 1990), presumably for lack of careful evaluation of habitat conditions at potential transplant sites or because of disease transmitted by livestock. [6]

Improvement of habitat for Bighorn Sheep in the U.S. has been frequent, especially on federal multiple-use lands. Projects have been funded with combinations of federal, state, and private moneys. Natural water sources have been improved and artificial water sources created, especially in the Mojave and Sonoran deserts of the Southwest. Further north, dense forest or shrub vegetation has been cleared, often by controlled burning, to provide open areas with forage for Bighorn Sheep. Some populations of Bighorn are routinely baited and treated with drugs to control parasites including lungworm (Protostrongylus sp.). Such treatments concentrate sheep and may jeopardize wildness. [6]

Management and research biologists exchange information on Bighorn Sheep in annual meetings of the Desert Bighorn Council and biennial meetings of the Northern Wild Sheep and Goat Council. Proceedings of these meetings are published.  [6]

Three private organizations, the Foundation for North American Wild Sheep, the Rocky Mountain Bighorn Society and the Society for the Conservation of Bighorn Sheep, raise funds for research and management. At least 10 states auction and/or raffle one or two special Bighorn hunting licenses to raise funds for these purposes. [6]

The status of most traditional subspecies and major ecotypes of Bighorn Sheep is satisfactory because they exist on 30 biological reserves and on many other protected areas. However, their status is not fully secure because at least 64 per cent of the herds contain about only 100 animals. Berger (1990) reviewed the history of some small Bighorn populations and concluded that those numbering less than 50 animals usually became extirpated, but Wehausen (1999) provides an alternative interpretation and viewpoint. Further, the ecotypes of Bighorn in the Chihuahuan desert and in shortgrass-badlands and riverbreak environments are not secure because there are few reserves or other protected lands within these two regions, and very few of these lands contain wild sheep. [6]

In Mexico the species is listed in Appendix II of CITES. Mexican Bighorn occur in only two protected areas in Mexico, one of which (Isla Tiburon Wildlife Reserve – in the Sea of Cortez) holds an introduced population. The putative Peninsular Bighorn is in only one protected area, Sierra de San Pedro Martir National Park, but putative Weem’s Bighorn occurs in none. A small group (25 in 1992) of Desert Bighorn (O. c. nelsoni) is held in captivity at Hermosillo.

Recreational Hunting

Hunting is well regulated and managed in Canada and the United States. For Mexico is was said in 2008 that hunting needs improvement. [6]

Hunting in Canada: Many populations can be hunted under license. Harvesting both adult males and adult females may be permitted in some populations. Hunting quotas are determined each year, and in general regulations are strictly enforced.

Alberta: Between 200 to 250 male and 150 to 200 female Rocky Mountain Bighorns are harvested annually in this province.

British Columbia: In this province only males are hunted: 60 to 65 Rocky Mountain and 40 to 45 „California Bighorns“ are shot each year, mainly by resident hunters (Hebert et al., 1985). Male harvest is limited only by the availability of adult males that have reached a minimum curl size, possibly leading to artificial selection against large-horned rams (Coltman et al., 2003). [6]

Hunting in the United States: Animals in about half the herds are hunted, and all states with Bighorn Sheep have at least one hunted population. Usually, only adult males are taken as hunting trophies. The number of sheep permitted to be taken each year is conservative and is regulated by each state. All states require that legally taken trophy heads be marked for permanent identification. This practice allows easy identification of illegally taken animals and thus discourages poaching. [6]

Hunting in Mexico: The high price ($ 30.000 to over $ l00.000) that some hunters are willing to pay to hunt wild sheep has motivated private and communal landowners in Sonora and Baja California to begin desert sheep monitoring and management programs. In 1994, ranchers in Sonora started a captive breeding program by capturing 40 sheep and placing them in breeding enclosures. Six hunting permits were issued to private landowners for free-ranging Bighorns in 1995, and each sold for $ 40.000. A private conservation organization has initiated a transplant of Bighorns from southern Baja California to Carmen Island. The excess sheep produced on this island are used to re-establish extinct populations on the mainland. The participation of private landowners in wild sheep management programs in Mexico is a positive initiative. Private landowners have the funds to provide for monitoring wild sheep populations and to prevent further poaching. [6] At least US$ 4,5 million have been generated from sheep hunts on Tiburon Island and an additional US$ 2,7 million from the sale of live animals. [16]

Ecotourism

Opportunities to watch Bighorns in North America are numerous (see the subspecies sections). Bighorns are also very adaptable to the presence of humans.

Literature cited

[1] Castelló, José R., 2016: Bovids of the World – Antelopes, Gazelles, Cattle, Goats, Sheep, and Relatives. Princeton University Press

[2] Damm, Gerhard R. and Franco, Nicolás, 2014: The CIC Caprinae Atlas of the World – CIC International Council for Game and Wildlife Conservation, Budakeszi, Hungary in cooperation with Rowland Ward Publications RSA (Pty) Ltd., Johannesburg, South Africa

[4] Groves, Colin and Grubb, Peter, 2011: Ungulate Taxonomy. The John Hopkins University Press

[5] Grzimek, Bernhard (Hrsg.), 1988: Grzimeks Enzyklopädie, Säugetiere, Band 5. Kindler Verlag, München

[6] Festa-Bianchet, M. 2008. Ovis canadensis. The IUCN Red List of Threatened Species 2008: e.T15735A5075259. http://dx.doi.org/10.2305/IUCN.UK.2008.RLTS.T15735A5075259.en. Downloaded on 19 March 2019.

[7] Matschei, Christian, 2012: Böcke, Takine & Moschusochsen. Filander Verlag

[10] Schaller, George B., 1977: Mountain Monarchs – wild sheep and goats of the Himalaya. The University of Chicago Press

[12] Shackleton, D. M (ed.) and the IUCN/SSC Caprinae Specialist Group, 1997: Wild Sheep and Goats and their Relatives. Status Survey and Conservation Action Plan for Caprinae. IUCN, Gland, Switzerland and Cambridge, UK. 390 + vii pp

[16] Wilson, D. E. and Mittermeier, R. A. [eds], 2011: Handbook of the mammals of the world. Vol. 2. Hoofed mammals. Lynx Edicions, Barcelona.