The Bighorn Sheep (Ovis canadensis)...
The Bighorn Sheep (Ovis canadensis) is a species of sheep in North America with
two endangered subspecies:
* Desert Bighorn Sheep (Ovis canadensis nelsoni),
* California Bighorn Sheep (Ovis canadensis californiana).
Wild sheep crossed the Bering land bridge from Siberia during the Pleistocene and, subsequently, spread through western North America as far south as Baja California and northern mainland Mexico (Cowan 1940). Divergence from their closest Asian ancestor (Snow Sheep) occurred about 600,000 years ago (Ramey 1993). In North America, wild sheep have diverged into two extant species -- Dall sheep that occupy Alaska and northwestern Canada, and bighorn sheep that range from southern Canada to Mexico. However, the status of these species is questionable given that hybridization has occurred between them in their recent evolutionary history (Loehr et al. 2005).
Bighorn sheep were amongst the most admired animals of the Apsaalooka, or Crow, people, and what is today called the Bighorn Mountain Range was central to the Apsaalooka tribal lands. In the Bighorn Canyon National Recreation Area book, storyteller Old Coyote describes a legend related to the bighorn sheep. A man possessed by evil spirits attempts to kill his heir by pushing the young man over a cliff, but the victim is saved by getting caught in trees. Rescued by bighorn sheep, the man takes the name of their leader, Big Metal. The other sheep grant him power, wisdom, sharp eyes, sure footedness, keen ears, great strength and a strong heart. Big Metal returns to his people with the message that the Apsaalooka people will survive only so long as the river winding out of the mountains is known as the Bighorn River.
Bighorn Sheep can be found in all of the southwestern deserts. In places
such as theGreat Basin, Mojave, Sonoran and Chihuahuan Deserts of southeast
California, Arizona and New Mexico. They reside in the foothills near rocky
cliffs and permanent water when seasonally available. Bighorn Sheep rarely
inhabit areas that are disturbed by humans. Bighorns spend their summers
9when applicable) high in the alpine zone on grass-covered slopes. In
winter, they may migrate a considerable distance to reach south or
southwest-facing slopes where snow cover is minimal.
The Bighorn is covered with a brown coat. It's belly, rump, back of legs,
muzzle and eye patch are all white. The male has a hard and thick set of
horns. The horns spiral backwards from the top of the head. The Bighorn
Sheep is an excellent climber and jumper.
Bighorns are generally active during the day, feeding morning, noon and
evening, then lying down to chew their cud. They retire to their bedding
areas for the night, which may be used for many years.
The rutting season is from mid-September to late October. During this time,
the males have butting contests where they "butt" each other with their
horns. During this, they can reach speeds of 50-70 miles per hour and an
estimated force of 2400 pounds.
Bighorn Sheep have superior eyesight and agility and therefore, have few
natural predators. What is threatening to them is destruction of their
natural habitat and diseases.
Audubon's bighorn sheep were native to the Black Hills and Badlands of
South Dakota. Uncontrolled hunting caused the extinction of this
subspecies of bighorn sheep by 1916. Therefore, the three herds now
in South Dakota are a result of transplanted sheep from other states.
In 1964, bighorn sheep from Wyoming were transplanted into Custer State
Park and sheep from Colorado were transplanted into the Badlands National
Park. The most recent transplant occurred in 1991, when 26 bighorn sheep
from Colorado were released in Spring Creek Canyon in the Black Hills.
Presently, there are approximately 300 to 350 bighorn sheep in South
Dakota among the three herds.
Bighorn sheep are very social animals and are generally separated into
two groups. One group consists of mature rams or ram bands, while the
other group consists of ewes, lambs, and young rams or nursery groups.
These groups join during the rut in mid-November through late December,
and occasionaly in early spring for a short period of time. Lambs, one
per ewe, are born in late May or early June. Very rarely will a ewe
have twins. Young rams will eventually break from the nursery groups
at two or three years of age and join the ram bands that are governed
by a social hierarchy based on body and horn size. Much head butting
occurs between mature rams during the establishment of the social
hierarchy, which determines what rams will dominate the group.After
dominance has been established, rams live in the same groups with
little further conflict. Life span is normally 10 to 12 years.