The Stone sheep is somewhat larger and chunkier than the Dall’s sheep, with a larger and relatively wider skull, and heavier, darker-colored horns.
A mature adult Stone ram (Ovis dalli stonei) has a body weight of about 180 to 220 pounds, but occasionally they can be 250 pounds or more. Females (ewes) are considerably smaller. It is a handsome animal, differing from the Dall’s mainly by not being white. Individuals vary greatly in color and pattern, ranging from more white in the north through shades of gray and brown to nearly black in some areas. Stone’s sheep with “lighter” coloring are often considered Fannin sheep.
Sheep of various colors may be found in the same group. The head, and often the neck, are a lighter color than the body. The muzzle, belly, backs of legs, and rump are white. The tail is black, and is usually connected by a dark band to the dark hairs of the back. Older rams sometimes have a dark band across, or partially across, the white belly. The Stone sheep is somewhat larger and chunkier than the Dall’s sheep, with a larger and relatively wider skull, and heavier, darker-colored horns. Horns are brown or dark amber and exhibit considerable variation in size and shape. Females have short, slender horns.
Stone’s sheep are usually found in alpine country, including glacier edges and below permanent snow line. Essential elements are steep, rugged cliffs and rock outcroppings for escape from predators, and nearby meadows for feeding.