Sierra Nevada bighorn sheep
| Sierra Nevada bighorn sheep | |
|---|---|
 |
|
| Herd at Wheeler Crest | |
| Scientific classification | |
| Kingdom: | Animalia |
| Phylum: | Chordata |
| Class: | Mammalia |
| Order: | Artiodactyla |
| Family: | Bovidae |
| Subfamily: | Caprinae |
| Genus: | Ovis |
| Species: | O. canadensis |
| Subspecies: | O. c. sierrae |
| Trinomial name | |
|
Ovis canadensis sierrae (Grinnell, 1912) |
|
Sierra Nevada bighorn sheep (Ovis canadensis sierrae) is subspecies of bighorn sheep unique to the Sierra Nevada mountains of California. A 2016 genetics study confirmed significant divergence between the three subspecies of North America's bighorn sheep: Sierra Nevada bighorn sheep, Rocky Mountain bighorn sheep and desert bighorn sheep. Sierra Nevada bighorn sheep were listed as a federally endangered subspecies in 2000. Today, about 500 Sierra bighorn remain in the wild.
Sierra bighorn range in color from white to dark brown, with a white rump and dark tail. There is some seasonal change in coloration due to the shedding of a thicker winter layer. Specialized hooves with adhesive soles provide traction in steep rocky terrain. Female bighorn (ewes) can weigh up to 70 kilograms (155 lb) and have shorter, narrow horns, while male bighorn (rams) can weigh as much as 100 kilograms (220 lb) and have massive, curving horns. The horns of both rams and ewes are composed of a dense layer of keratin covering a core of bone.
The average lifespan for Sierra bighorn males and females has been observed as 8 to 12 years.
Sierra Nevada bighorn sheep are gregarious, with group size and composition depending on gender and season. Spatial segregation by gender occurs outside of the mating season. Bighorn sheep ewes generally remain with the same band in which they were born. Males older than 2 years of age remain apart from females and younger males for most of the year. During the late fall and winter, the groups come together and concentrate in suitable winter habitat. During this time, males compete for dominance with behaviors like horn clashes. Breeding takes place in late fall, generally November and December. Lambing occurs between late April and early July on safe, precipitous, rocky slopes; most lambs in the Sierra Nevada are born in May and June. Ewes and lambs often occupy steep terrain that provides a diversity of exposures and slopes for escape cover.
Sierra bighorn are found in portions of the Sierra Nevada from Yosemite National Park to Olancha Peak. Habitat occurs from the eastern base of the range as low as 1,460 m (4,790 ft) to peaks above 4,300 m (14,100 ft). Sierra bighorn inhabit open areas where the land is rocky, sparsely vegetated, and characterized by steep slopes and canyons. Wehausen provides a detailed description of Sierra bighorn habitat throughout their range. Bighorn prefer open ground with high visibility to better detect predators and allow enough time to reach steep, rocky areas (escape terrain). Forests and thick brush are usually avoided if possible.
...
Wikipedia