The Dall sheep Ovis dalli, is a species of sheep

Ovis

Ovis is a genus of mammals, part of the goat-antelope subfamily of the ruminant family Bovidae. Its five or more highly gregarious species are known as sheep...

 native to northwestern North America, ranging from white to slate brown in color and having curved yellowish brown horns. Its closest relative is the more southern Stone sheep (also spelled Stone's sheep) (Ovis stonei), which is a slaty brown with some white patches on the rump and inside the hind legs.

Research has shown the use of these subspecies designations is questionable.