I spent this past weekend photographing bighorn sheep near Georgetown, Colorado. I like working the bighorn. They can be found fairly close to my home, so getting to them isn’t much of a problem.
The best time to search for them is generally after a good mountain snow and in cold temperatures. The sheep come down from their higher habitat looking for grass that is more accessible. Typically, they’ll stick to open areas of grass below steep hills, on southernly facing slopes. Mid November is prime time for rutting and I had some good luck finding quite a few Rams chasing ewes and squaring off with one another.
Bighorn are native to North America. There are three distinct species and several subspecies in North America. Rocky Mountain Bighorn, Dall Sheep and Desert Bighorn. Rocky Mountain Bighorn and Desert Bighorn are both present in Colorado, Dall Sheep are more common in Alaska and British Columbia.
Bighorn are quite susceptible to pneumonia and outbreaks spread quickly through herds. They are also hunted in Colorado and other states.
In a general sense, bighorn are not aggressive towards humans but they can become defensive and will knock a human pretty hard if they feel threatened. For the most part though, a bighorn defensive act usually involves them retreating to higher rock covered hillsides where they are protected from predators. A bighorn sheep can scale nearly vertical cliffs and move with ease in terrain that no other animal will go into. It’s simply amazing to watch these animals move around on rocky hillsides as though they haven’t a care in the world. Mating occurs most frequently in Mid-November and the female sheep (ewes) have a gestation period of about 6 months. The rut begins in late October and the Rams will attempt to mate into mid-late December. After the rut, the mature rams generally break off into bachelor herds and the females will stick together with younger sheep in nursery herds.
The Rocky Mountain Bighorn (pictured here) is the state animal of Colorado. The Desert Bighorn is the state animal of Nevada.
Bighorn sheep typically weigh about 315 lbs when fully grown. Their horns can weigh as much as 30 lbs. When two Rams butt heads in combat, the sound of the horns colliding is loud and distinctive, sounding something akin to two bowling balls colliding at high speed. The crashing sound can be heard from a mile away. I’ve personally witnessed several bighorn ram fights over the years, but it is very difficult to see it happen in photographic view. The challenge to fight is a ritual mating behavior that involves two rams of similar build pushing, kneeing and mounting one another. When the head butting sequence begins, the two males will separate and face one another from about 15 feet away. They’ll then raise up on their hind legs and lunge at one another headfirst and their horns will collide. Often the force of the impact is enough to cause a ram to twist and turn in the air. It’s an amazing thing to watch.
Healthy bighorn can live for 9-14 years. One can roughly estimate the age of a ram by the growth patterns on their horns. Distinctive growth rings appear on their horns each year. A typical 5-year-old adult ram will have roughly a half curl in their horns. It takes about 10 years for a ram’s curl to be completely circular. The rams will grind off the tips of their horns on rocks to improve their vision as well. Unlike deer, moose and elk, bighorn sheep don’t shed their horns each year. The horns stay with the ram until death, or they become damaged and break off. I’ve seen numerous mature males with broken and seriously damaged horns. A lot of the damage is a result of years of combat.