Bighorn Sheep are the symbol of Rocky Mountain
Rams Actually Do Ram
There are no larger wild sheep in North America but the Rocky Mountain bighorn sheep. The average muscular male weighs more than 300 pounds and stands over three feet tall at the shoulder. The size of a female is roughly half that of a male. Gray to dark brown in color, bighorn sheep have white patches on their rump, muzzle, and back legs.
Winter coats are typically thick, double-layered, and light in color. During the summer, bighorn sheep shed their heavy coats. Wide-set eyes provide a wide field of view. This, in combination with sharp hearing and a highly-developed sense of smell, allows one to detect dangers at a great distance. Specialized hooves and rough soles allow bighorn sheep to climb steep cliff faces and jump from precarious heights.
As their name implies, bighorn sheep have horns that remain on their heads throughout their life. The horns of males, called rams, curl around their faces by the age of eight. Weights can reach 30 pounds for these horns. During the first four years of life, the horns of females, called ewes, curve slightly to a sharp point.
A bighorn sheep usually lives in social groups, but rams and ewes only mate together. The rams live in bachelor groups and the ewes live in herds with young lambs. Lambs are born in the spring and begin walking soon after birth. A nurse can provide care for up to six months. A male leaves his mother’s group at around the age of two to four, while a female stays with her herd for life.
The bighorn sheep eat grass in the summer and browse shrubs in the fall and winter.
Salt licks, such as Sheep Lakes, provide minerals for their diet. As a survival mechanism, their digestive system functions. Sheep have a complicated, four-part stomach that allows them to gain nutrients from hard, dry forage. After eating large amounts of vegetation, they retreat to cliffs or ledges. The whole process of digesting their food can be done away from predators in this area.
Bighorn sheep live for approximately ten years. Mating occurs in the fall when rams fight for territory or mating rights with their horns. Rams face each other, rear up on their hind legs, and pitch forward at speeds up to 40 miles per hour during the rut. It is possible to hear the loud crash of horns from one mile away, signaling contact. Repeat this ritual until the animal gives up and walks away.
Bighorn sheep are boney and thick, which makes their skulls able to absorb repeated impacts with little damages to the rams.
From the Mummy Range to Sheep Lakes in Horseshoe Park, bighorn sheep descend to low elevations in late spring and early summer.
Grazing and eating soil provide minerals they don’t get in the high mountains. Mineral supplements restore nutrient levels depleted by the stress of lambing and poor nutrition during the winter.
Sheep in groups of one to sixty move from the north side of the valley across the road and spend up to two to three hours there, before turning around and returning to the high country. Crossing the highway causes animals to experience higher levels of stress, resulting in reduced resistance to disease and increased mortality rates.
Horseshoe Park created a “Bighorn Crossing Zone” to protect the sheep. As sheep move from and to the meadow in late spring and throughout the summer, rangers control traffic.
Researchers say this is resulting in sheep consuming more minerals, thereby improving their health. Rocky Mountain National Park’s recent history of bighorn sheep is one of near extinction and encouraging recovery. In the 1900s, bighorns were often shot by the hundreds by market hunters, who then sold their prized horns and meat for high prices.
Since ranchers moved into mountain valleys, important bighorn habitats were altered, and domestic sheep were introduced. Domestic sheep carried scabies and pneumonia, which proved fatal for many bighorn sheep.
In the 20th century, disease, hunting, and habitat alteration caused the bighorn population to decline. Around 150 bighorns were recorded in the area of the national park in the 1950s. Herds of bighorns were found in less accessible areas.
There was only a limited range of these animals in the isolated high country areas of the Mummy and Never Summer mountain ranges.
Populations of bighorns returned to health in the 1960s and 1970s as hunting pressure and disease declined. The North St. Vrain River and Cow Creek were reintroduced to the bighorn sheep’s historic range in 1978 and 1980, stimulating population growth.
The number of bighorn sheep along the eastern boundary of the park, as well as the number of surviving native herds, have remained stable. There are currently 350-400 bighorn sheep in the Rocky Mountain National Park area.