Despite its name a mountain goat (Oreamnos americanus) is actually not a member of the actual goat genus. Mountain goats belong to a group known as goat-antelopes. The natural range of the mountain goat includes southern Alaska and Yukon, British Columbia, northern Idaho, northwest Montana and parts of Washington. British Columbia contains more than half of the world’s population of mountain goats.
Mountain goats have the thickest and longest pelage of any North American ungulate aside from the muskox. Their coats are white and usually fairly shaggy, including hollow guard hairs up to 20 cm long and a fleecy undercoat that is 5 to 8 cm long. Both sexes sport a noticeable beard, which is longer in winter. Mountain goats have a deep chest and well-developed shoulder muscles that give them great strength for climbing and pawing for food in the winter. A mountain goat’s cloven hooves have rough, textured traction pads that project past the rim of the hooves, which makes them conducive to rocky and slippery terrain.
Both sexes have long ears and narrow, black, short, sharply pointed horns. A nanny’s horns are more slender at the base and a bit more curved at the tip than a billy’s horns. A mountain goat’s horns will grow continuously and never be shed. The growth rings or annuli on the horns indicate age. During mating season a male often marks a female with a musky oil from glands at the base of his horns by rubbing his head against her body.
Most mountain goats graze above the tree line and survive by eating a wide variety of plants including lichens, ferns, grasses, herbs, shrub and deciduous or coniferous trees. A mountain goat’s weight will vary from 120 to 265 lbs (55 to 120 kgs), depending on its gender and food supply.