The wild sheep ranks highest among the animal mountaineers of the Sierra.  Possessed of keen sight and scent, and strong limbs, he dwells secure amid the loftiest summits, leaping unscathed from crag to crag, up and down the fronts of giddy precipices, crossing foaming torrents and slopes of frozen snow, exposed to the wildest storms, yet maintaining a brave, warm life, and developing from generation to generation in perfect strength and beauty.

Nearly all the lofty mountain-chains of the globe are inhabited by wild sheep, most of which, on account of the remote and all but inaccessible regions where they dwell, are imperfectly known as yet.  They are classified by different naturalists under from five to ten distinct species or varieties, the best known being the burrhel of the Himalaya (Ovis burrhel, Blyth); the argali, the large wild sheep of central and northeastern Asia (O. ammon, Linn., or Caprovis argali); the Corsican mouflon (O. musimon, Pal.); the aoudad of the mountains of northern Africa (Ammotragus tragelaphus); and the Rocky Mountain bighorn (O. montana, Cuv.).  To this last-named species belongs the wild sheep of the Sierra.  Its range, according to the late Professor Baird of the Smithsonian Institution, extends “from the region of the upper Missouri and Yellowstone to the Rocky Mountains and the high grounds adjacent to them on the eastern slope, and as far south as the Rio Grande.  Westward it extends to the coast ranges of Washington, Oregon, and California, and follows the highlands some distance into Mexico."[1] Throughout the vast region bounded on the east by the Wahsatch Mountains and on the west by the Sierra there are more than a hundred subordinate ranges and mountain groups, trending north and south, range beyond range, with summits rising from eight to twelve thousand feet above the level of the sea, probably all of which, according to my own observations, is, or has been, inhabited by this species.

Compared with the argali, which, considering its size and the vast extent of its range, is probably the most important of all the wild sheep, our species is about the same size, but the horns are less twisted and less divergent.  The more important characteristics are, however, essentially the same, some of the best naturalists maintaining that the two are only varied forms of one species.  In accordance with this view, Cuvier conjectures that since central Asia seems to be the region where the sheep first appeared, and from which it has been distributed, the argali may have been distributed over this continent from Asia by crossing Bering Strait on ice.  This conjecture is not so ill founded as at first sight would appear; for the Strait is only about fifty miles wide, is interrupted by three islands, and is jammed with ice nearly every winter.  Furthermore the argali is abundant on the mountains adjacent to the Strait at East Cape, where it is well known to the Tschuckchi hunters and where I have seen many of their horns.