Which sheep native to North America is also known as the thinhorn sheep?

The Dall sheep, also known as the thinhorn sheep, ('Ovis dalli') is a species of wild sheep native to northwestern North America, ranging from white to slate brown in colour and having curved, yellowish-brown horns. The two subspecies are the nominate Dall sheep or Dall's sheep and the more southern subspecies, Stone sheep (also spelled Stone's sheep) (O. d. stonei), which is a slate brown with some white patches on the rump and inside the hind legs.

During the summer when food is abundant, the sheep eat a wide variety of plants. The winter diet is much more limited, and consists primarily of dry, frozen grass and sedge stems available when snow is blown off, lichen, and moss. Many Dall sheep populations visit mineral licks during the spring, and often travel many miles to eat the soil around the licks.