Posing Bighorn Sheep

Found these bighorn sheep on a trip to Leslie Gulch State Park in Eastern Oregon.
The Owyhee Bighorn Sheep disappeared at the turn of the... more

by Robert Bales

Title

Posing Bighorn Sheep

Artist

Robert Bales

Medium

Photograph - Photo

Description

Found these bighorn sheep on a trip to Leslie Gulch State Park in Eastern Oregon.
The Owyhee Bighorn Sheep disappeared at the turn of the century. It was due to the competition of livestock and over hunting. In 1965 the Bureau of Land Management and the State of Oregon reintroduced 17 of the California Bighorn Sheep and by 1980 there was over 100 in the area.
The bighorn sheep (Ovis canadensis) is a species of sheep in North America named for its large horns. These horns can weigh up to 30 lb (14 kg), while the sheep themselves weigh up to 300 lb (140 kg). Recent genetic testing indicates three distinct subspecies of Ovis canadensis, one of which is endangered: O. c. sierrae. Sheep originally crossed to North America over the Bering land bridge from Siberia: the population in North America peaked in the millions, and the bighorn sheep entered into the mythology of Native Americans. By 1900, the population had crashed to several thousand, due to diseases introduced through European livestock and overhunting. Conservation efforts (in part by the Boy Scouts) have restored the population.
In Californa, the desert bighorn, Ovis canadensis, is found in the dry, desert mountains of southeastern California. The most evident feature of desert bighorn sheep is the large curled brown horns that continue to grow throughout their lives. Both rams (males) and ewes (females) have horns, though the horns of rams are much larger and more curved. The horns are permanent and consist of a sheath of keratin (a hard protein found in fingernails and hair) covering a boney core. By the time a ram is seven or eight, he can have a set of horns with a full curl, a spread of 30 inches, and a skull and horn weight of 20 pounds or more. Horn size is a symbol of rank among males. Many rams break off the ends of their horns (called "brooming"), often during horn clashes for dominance. Ewes are smaller than rams and have shorter, less massive horns that never exceed half a curl. Desert bighorn ewes grow longer and larger horns than Sierra Nevada or Rocky Mountain females. Bighorn coat color varies among bighorn sheep. The coat is typically dark brown or gray, while it tends toward lighter in some animals. The large white rump, strongly constrasting with the body color, often aids people in spotting sheep from a distance.The desert bighorn is most active during daylight, often moving to steeper terrain to bed at night. During the summer bighorn sheep rest during the hottest part of the day, usually under some form of shade.
Desert bighorn sheep detect predators primarily with very keen eyesight and escape them through great agility in steep rocky slopes (escape terrain)
Bighorn sheep are gregarious, typically forming herds, rarely exceeding 20 individuals. During periods of scarce water and food they sometimes can be found alone. For much of the year, adult rams are segregated from ewes and the young in separate bachelor bands.
Rams engage in battles to determine dominance. Dominance is expressed via visual displays. Dominance interactions include displacement from a bedding site, kicking, butting, neck wrestling, and fights; horn clashes are the most widely known of these interactions. A horn clash can sound like a rifle shot, and can be heard for long distances during battles. The most dominant rams are typically those with the largest bodies and horns. Dominance allows mating access to estrous females. Rutting activity usually peaks in August and September but can occur over a six month period or longer. Bighorn sheep follow a poygynous mating strategy whereby the dominant males do most of the breeding.

Uploaded

April 23rd, 2014