Overview
The North and South Baja Desert Bighorn sheep resemble each other, and more information is needed on the differences in physical characteristics between these two subspecies. This subspecies is somewhat darker than its counterparts. South Baja Desert Bighorn ewes have the longest horns of all the Desert Bighorn subspecies. Desert bighorns are also smaller than Stone sheep, Dall sheep, and Siberian snow sheep. Females are about 60 percent as large as males.
Taxonomy
- Kingdom
- Animalia
- Phylum
- Chordata
- Class
- Mammal
- Order
- Artiodactyla
- Family
- Bovidae
- Genus
- Ovis
- Species
- Bighorn sheep, canadensis
Habitat
Desert mountains with sufficient permanent water. Water is essential. Desert sheep may forage over considerable distances, and must drink every few days during hot weather.
Diet
Bighorn sheep feed on grasses in the summer and browse shrubs in the fall and winter, and compared to the California Bighorn, consumes more browse and less grass. They seek minerals at natural salt licks to add nutrients to their diet.
Behavior
These animals have wide-set eyes that provide a large angle of vision, as well as sharp hearing and a highly developed sense of smell, allowing Bighorns to detect dangers at great distances. The sexes remain separate except during the breeding season. Lambs are born in the spring, walk soon after birth, and nurse for six months. Rams will determine their hierarchy at the start of the breeding season, and males may ram each other headfirst at speeds up to 40 mph (64 kmh). This act is repeated until one animal concedes. Bighorn sheep skulls are thick and bony to absorb this repeated impact and prevent injury to the ram.
Hunting
Limited permits are available. Hunting this sheep is expensive and physically demanding.
Conservation Status
Populations are secure but not considered plentiful. They are under constant pressure from loss of habitat, competition from domestic livestock, and diseases transmitted by domestic sheep. There are at least 51 species of parasites known to affect bighorn sheep, 36 of which are carried by domestic sheep and 18 by cattle. Bighorns are particularly vulnerable to pneumonia brought on by lungworm infection, and catastrophic die-offs have sometimes occured. The IUCN status (2002) of Ovis canadensis (all subspecies) is listed as low risk/conservation dependent. Bighorn sheep subspecies in North America were estimated at 1.5 to 2 million during the pre-Columbian periods (Seton 1929). By 1960, the population of bighorn sheep in North America dropped to 15,000-18,000 (Buchner 1960), and the total desert bighorn sheep population was estimated at 7,065-8,475 (Buchner 1960). However, due to conservation by government and non-government groups, the 1993 overall desert bighorn sheep population increased to 18,965-19,040. The endangered peninsular bighorn sheep, a population of desert bighorn sheep, was estimated at 780-1,170 in Baja California, Mexico in 1993. Census from Sharkleton in 1997 had Ovis canadensis canadensis at = 36,700; O. c. californiana at 8,900; O. c. nelsoni at 15,000; O. c. Mexicana greater than 2,000; O. c. cremnobates at less than 2,500 and O. c. weemsi at 500. Ovis canadensis cremnobates IUCN status = endangered. Listed as endangered in 1998 by U.S.F.W.S. The latest population estimate (excluding lambs) was 334 (Rubin 1998).