Recognized by their large curved horns, bighorn sheep (Ovis Canadensis) have become one of the most recognizable symbols of the mountainous western United States. This powerful mammal is believed to have entered North America using the land bridge that once connected the continent with Asia. Prior to the 1900’s, it is estimated that bighorn sheep numbered in the millions, but hunting, competition from domestic sheep and habitat loss had reduced their population to only a few thousand by the beginning of the 20thcentury. Conservation efforts led by the Boy Scouts of America began in the 1930’s and have done much to restore the distribution of this regal animal.
Bighorn sheep are easily differentiated from their domestic cousins. They have a brown coat with white underbelly and rump, a very short tail, and large horns; these horns can weigh up to 30lbs on males, and are significantly smaller and less curved on females. Males are significantly larger, and usually weigh between 125-300lbs, though some subspecies’ in mountainous regions can weigh nearly 500lbs. Females on the other hand weigh up to 200lbs, with some as small as 75lbs.
The range of bighorn sheep stretches from the Rocky Mountains in Canada and the United States south to parts of Texas, New Mexico, Arizona, California, and Northern Mexico. Bighorn sheep usually live on and around mountain slopes, foothills, and high meadows. Their summers are usually spent at up to 8500 feet in the mountains, where their superior climbing ability allows them to avoid predators such as wolves and mountain lions. When winter comes, the bighorns will descend to meadows at lower altitudes, as they are not equipped to travel efficiently through deep snow.
Bighorn sheep live in flocks of up to 100 animals, with the usual size being 8-10. Flocks are separated by sex and age, with mature males forming their own flocks, and females and lambs of both sexes living in flocks of their own. Bighorns are grazing animals, and primarily subsist on grasses and vegetation native to their area. When food is scarce they will also eat twigs, leaves and shoots, though this is not preferable.
Bighorn sheep have a very well-known mating ritual in which mature rams will clash horns, running at each other at up to 20mph. These contests, which are used to establish dominance, can last up to 20 hours, with the winner usually being able to mate with more or preferable females. Ewes will give birth to their lambs along ledges, cliffs, or any other area that is difficult for a predator to access. Newborn lambs are able to walk within a few hours, and will depend on their mother for milk for the first 4-6 months of life. At 2-4 years old, young rams finally leave their mothers and join a flock of other rams; ewes will likely stay in the same flock as their mother for life.
BIGHORN SHEEP FACTS
- The average lifespan of a bighorn sheep is 9-14 years
- The Rocky Mountain Bighorn Sheep is the state animal of Colorado
The Bighorn Institute