Rocky Mountain goat, hoofed ruminant mammal, Oreamnos americanus, found in the high mountains of S Alaska, W Canada, and the extreme NW United States. Although it is not a true goat it belongs to the same family (cattle family) and is goatlike in appearance, with a bearded chin, long face, and sharp, black horns 9 to 12 in. (22–30 cm) long, curved slightly backward. The head is large and the neck short. The coat is long, thick, and pure white. The male is about 3 ft (90 cm) high at the massively humped shoulder and weighs up to 200 lb (90 kg). Rocky Mountain goats live in small herds on steep mountain sides and cliffs, feeding on the stunted vegetation above the timberline. They are extremely sure-footed and nimbly traverse precipitous slopes and ledges. Related to the Old World chamois, the Rocky Mountain goat is classified in the phylum Chordata, subphylum Vertebrata, class Mammalia, order Artiodactyla, family Bovidae.