Interesting as the desert varieties of this species may be in their adaptation to an environment that seems foreign to their nature, they cannot compare with the high mountain animal. Seen against the backdrop of a great gray cliff or silhouetted against the skyline of a snowy crest the bighorn has a magnificence that is thrilling. In flight it is even more spectacular as it bounds from one narrow shelf to another in an incredible show of surefootedness. Yet this airy grace is exhibited by a chunky animal that often weighs well over 200 pounds. The secret lies in the specially adapted hooves with bottoms that cling to smooth surfaces like crepe rubber and edges that cut into snow and ice or gain a purchase on the smallest projections of the rocks. The legs and body, though heavy, are well proportioned and so extremely well muscled that no matter what demands are placed on them this sheep seems to have a comfortable reserve of power. No doubt the display of complete coordination adds to the illusion of ease with which it ascends to the most inaccessible places. Descents often are even more spectacular, the animal seldom hesitating at vertical leaps of 15 feet or more down from one narrow ledge to another.
bighorn
In the high mountains where this sheep prefers to make its home it usually ranges near or above timberline. During winter storms it may sometimes be forced down into the shelter of the forests, but as soon as conditions warrant it will go back to its world of barren rocks and snow. Here, with an unobstructed view, its keen eyes can pick out the stealthy movements of the mountain lion, the only mammal predator capable of making any serious inroads on its numbers. It has few other natural enemies. A golden eagle occasionally may strike a lamb and knock it from a ledge, or a high ranging bobcat or lynx may be lucky enough to snatch a very young one away from its mother, but these are rare occurrences.
Bighorns depend mainly on browse for food. This is only natural since in the high altitudes they frequent little grass can be found. Usually there is some abundance of low shrubs growing in crevices on the rocks, however, and many of the tiny annuals are also searched out during the short summer season. At times a sheltered cove on the south exposure of a mountain will become filled with such shrubs as the snowberry, and the sheep take full advantage of such situations. As a rule they keep well fed for, scanty though it seems, there are few competitors for the food supply above timberline.
I have observed these sheep many times in the Rockies. Perhaps my most memorable experience with this species was on Mount Cochran in southern Montana. It was a gray, blustery day in September with occasional snow flurries sweeping about the summits. On the eastern exposure of the mountain a steep slope of slide rock extended for perhaps 1,000 feet from one of the upper ridges to timberline. Not expecting to see any game at that elevation, I made my way up this slope with no effort to keep quiet. In my progress several rocks were dislodged and went rattling down across the mass of talus. At the summit of the ridge a low escarpment made a convenient windbreak against the gale that was tearing the clouds to shreds as they came drifting up the opposite slope, and I sat down to catch my breath before entering its full force. As I sat there surveying the scene spread out below, my attention was attracted by a low cough close by. Looking to the left about 40 feet away and 15 feet above me, I saw two magnificent rams standing on a projecting point looking down at me. They seemed to have no fear; rather they evinced a deep curiosity as to what strange animal this was that had wandered into their domain. For the better part of a half hour I hardly dared breathe for fear of frightening them. At first they gazed at me fixedly, occasionally giving a low snorting cough and stamping their feet. Then as I did not move, they would wheel about and change positions, sometimes taking a long look over the mountains before bringing their attention back. Finally when the cold had penetrated to my very bones, I stood up. They were away in a flash, reappearing from behind their vantage point with two ewes and an almost full-grown lamb following them. While I watched they dashed at a sheer cliff that reared up to the summit, and with hardly slackening speed bounded up its face until they were lost in the clouds.
Although this happened in 1928 the experience is as vivid in my mind as though it happened yesterday. Perhaps the most striking feature of bighorns seen at this close range is the eyes. They might be described as a clear, golden amber with a long oval, velvety black pupil. Credited with telescopic vision, they must be some of the most useful as well as beautiful eyes to be found in the animal kingdom.
Pronghorn (antelope)
Antilocapra americana (Latin: antelope and goat, American)
Range: West Texas, eastern Colorado and central Wyoming to southern California and western Nevada, and from southern Saskatchewan south into northern Mexico.
