STATUS of International Union for Conservation of Nature (IUCN) for 2002 Ovis canadensis (all subspecies): a low risk| depends on the protective measures. The population of bighorn sheep in the pre-Columbian era was about 1,5-2 mio animals (Seton, 1929). By 1960, their population in North America had declined to 15-18 thousand (Buchner, 1960), the population of Desert Bighorn Sheep was estimated in 7065- 8447 individuals. Thanks to the protective measures of the authority and other non-state organizations, their population has increased to 18965-19040 in the end of 1993. The endangered subspecies of the peninsular bighorn numbered 780-1170 individuals in Baja California, Mexico in 1993.
The accounting was made by Sharkleton in 1997. Ovis canadensis canadensis = 36700; O. c. californiana = 8900; O. c. nelsoni = 15000; O. c. Mexicana more then 2000; O. c. cremnobates менее 2500 and O. c. weemsi = 500. Status IUCN Ovis canadensis cremnobates = endangered species. In 1998 it was added to the list of endangered species of U.S.F.W.S. The last accounting was done in 1998 (Rubin). The population numberd 334 animals.
CLASSIFICATION The Desert Bighorn Sheep category includes four subspecies described by Cowen in 1940: Nelsoni bighorn, Mexicana bighorn, Crembobates bighorn and Weemsi bighorns.
There are three subspecies of the Desert Bighorn Sheep in Mexico. They are officially recognized by zoologists, have scientific credibility. Their reliability is based on anatomical differences and biogeographic considerations. All three Mexican subspecies were studied on samples from Mexico, which show regional differences.
DESCRIPTION (male) Males are tall at the shoulder (90 cm) and weight 68-77 kg. The adult sheep (127-157) long from the nose to the tail, tall at the shoulder (81-101 cm). Male bighorn sheep have large horn cores, enlarged cornual and frontal sinuses, and internal bony septa. The horns make a full turn to 7-8 years, the width to 84cm, weight to 13 kg. Females are about in 40% smaller than males. The scull of a desert bighorn sheep is smaller, ears are bigger and wool color is not so bright and wool is not long. They are smaller than Stone and Dall sheep and even Russian snow sheep. The white mirror has smaller size and is divided into two parts by the black line of a tail.
Horns have the same size as Rocky Mountain sheep’ horns but not twisted so much. The horns look huge because of the smaller body size and short wool. They seem disproportionately large in relation to the body. The ewes have short and thin horns.
The wool coat of the Mexican bighorn consists of a smooth brittle guard hair and a short and soft wavy undercoat of gray color. Their wool is light brown in color, paler than that of the American bighorn.
The HABITAT is a desert consisting of arid lowlands separated by bare, often free-standing mountains. Sometimes a sufficient number of trees and tree-like cacti are found in the habitat area. Temperatures range from about 10°C in January to 35°C in July. Average precipitation: from almost zero in the western regions to 25 cm in the east. The altitude from sea level is almost 1500 meters. Typical vegetation: desert acacia, ironwood, mesquite tree, giant cereus.
Description by selected species
Nelson's bighorn sheep
(Nelson Desert Bighorn Sheep)
Ovis canadensis nelson
It's was named after the American biologist Edward Nelson in 1897. DISTRIBUTION: Arizona: northwestern part of the state. California: The southeastern part, mostly in the Mojave Desert, but also in the southernmost areas of the Colorado Desert. Colorado: southwest, south of the Colorado River and west of the Gunnison River. Nevada: Southern part. Texas: Western part. Utah: southwestern and south-central parts of the state.
STATUS: Hunting is allowed. The limited number of hunting permits are sold in the auctions in Arizona, Nevada and some other states, but only few of them can be booked by the foreign hunters.
Mexican bighorn sheep
(Mexican Desert Bighorn Sheep).
Ovis canadensis mexicana
DISTRIBUTION Mexico: Sonora Desert in the state of Sonora. Wild populations have previously lived in the states of Chihuahua and Coahuila, but have been exterminated; they are restored with help of animals caught in Sonora state. They habitat in Mexico and on the island of Tiburon. USA: Arizona: southwest corner of the state. New Mexico: southwest corner of the state.
STATUS Hunting is allowed. They are managed by private landowners.
North Baja Desert Bighorn Sheep
Ovis canadensis cremnobates
DISCRIPTION The North Baja Desert Bighorn Sheep is the largest of the three subspecies that inhabit Mexico (Mexican, North Baja Desert Bighorn Sheep, and Weems' bighorn sheep,). Its body size is 20% larger, and its horns are about 16% larger.
HABITAT In the state of Baja California, the territories occupied by the desert bighorn in the north (cremnobates) differ significantly in characteristics from the bighorn habitat in the south of the state (weemsi). Biogeographers divide Baja California into sub-regions based on climate differences, as well as differences in flora and fauna.
DISTRIBUTION The peninsular bighorn lives in the territories from the border of Mexico and the United States in the north to the 28° parallel in the south. The southern boundary of the habitat runs in a straight line along the peninsula from the island of Isla Navidad in the west, through the city of Guerrero Negro and further east to the Gulf of California.
NOTES At the moment, the population is not subject to hunting. No public or private organizations are working on changing the status.
Weems' bighorn sheep
(South Baja Desert Bighorn Sheep)
Ovis canadensis weemsi
DESCRIPTION Anatomical differences include more than just horns. The color of the Weems' bighorn sheep is darker than other desert bighorns, and ewes have the longest horns of all wild sheep in North America.
THE HABITAT a segment of the peninsula with a length of 1000 km. The habitat consists of an irregular, sometimes interrupted line of rocky formations extending to the south and north of the peninsula, decreasing in an easterly direction. The terrain is diverse, including mountain ranges, hills, plateaus, canyons, and zanders, mostly granite or lava. The bighorns mostly live on the eastern side of this long chain. Precipitation here falls mainly in summer and early autumn, averaging 9-12 cm per year. Sometimes there are showers. The climate is warm, with an average annual temperature of about 23°C.
DISTRIBUTION The habitat is limited to the southern part of the Baja California Peninsula. This subspecies dwell south of the 28th parallel, south of the straight line from the island of Isla Navidad through the city of Guerrero Negro and further east to the Gulf of California.
The southern subspecies (weemsi) lives in the Sierra de la Higanta biogeographic region of Baja California, the Sierra de la Higanta mountain range. This mountain range starts 25 km south of Baia de Concepcion and ends in the north of Baia de la Paz. Also, the subspecies inhabitant on the island of Carmen. The habitat is clearly defined geographically and biogeographically, so it is not surprising that the anatomical differences of the subspecies (weemsi) so pronounced in comparison with the northern subspecies.
STATUS Hunting is allowed. The population in southern Baja California is tightly controlled by the Mexican government and private landowners. It has helped to form the population that allows hunting, although it is still small.
