Rocky Mountain goat is a sure-footed goat antelope found in the Rocky Mountains and in coastal regions of North America from Alaska to north-central Oregon and western Montana. The Rocky Mountain goat (Oreamnos americanus) belongs to the family Bovidae, in the order Artiodactyla, class Mammalia. Bovidae also includes sheep, cattle, bison, and bighorn sheep.
Physical Characteristics and Habitat
Oreamnus americanus is characterized by humped shoulders, a head that is typically held low, and a thick, wooly, white or yellowish white coat that provides excellent camouflage on snow-covered mountains, protecting species members from their natural enemies, which include cougars, wolves, and bears.
The fur forms an erect mane along the middle of the back from the horns to the base of the tail, with chin fur providing a distinct beard. Rocky Mountain goats have a head-and-body length of 47 to 63 inches (120 to 160 cm), a tail length of 4 to 8 inches (10 to 20 cm), a shoulder height of 35 to 47 inches (90 to 120 cm), and a weight of 100 to 310 pounds (46 to 140 kg).
Both sexes have slender, smooth, sharply pointed, black horns, which rise abruptly and curve backward about 8 inches. A hard, sharp rim enclosing the soft inner pad of each hoof allows the goats to climb and leap adroitly over rocks and ice. Mountain goats inhabit steep slopes and cliffs in cold, snowy alpine tundra and subalpine areas.
Reproduction, Development, and Longevity
Mating occurs from November to early January, with females giving birth to one or two offspring (called kids) in the spring, following a gestation period of approximately 186 days. Newborns weigh approximately 7 pounds (3 kg).
Both males and females reach sexual maturity at about 30 months of age. In the wild, males have a maximum-known longevity of about 14 years, while females can survive to 18 years of age.
Behavior, Diet, and Environmental Status
During winter months mountain goats tend to congregate in large herds, but through the rest of the year, adult males are solitary and females and subadults live in groups of, usually, no more than four animals.
Species members are extraordinarily agile, skillfully traversing ice-covered mountain tops, cliffs, and crags. Spending much of their time feeding, mountain goats are typically active in the early morning and late afternoon, although they can be found moving about at night as well.
The animals often sleep in a shallow depression excavated with their forefeet. As cold weather approaches, O. americanus retreats to lower altitudes, occupying southern- and western-facing slopes, which are typically snow free during winter months.
Social behavior appears to vary. Some researchers believe that males are dominant over females, whereas other reports indicate that the reverse is true. Throughout most of the year, however, the sexes appear to pay little attention to one another and will even battle over limited food resources.
Mountain goats consume a variety of plant materials, including moss, lichens, grass, herbs, woody plants, and the foliage of assorted mountain vegetation, with diets changing from one region to the next and from season to season. Salt licks provide an important component of their diet in the spring and summer months.
Although sport hunting by humans has seriously depleted some O. americanus populations, the Rocky Mountain goat has been less affected by this activity than have other North American big-game animals largely because it occupies remote terrain that is difficult to access. Mountain goats have been successfully introduced into Colorado, central Montana, the Black Hills of South Dakota, northeastern Oregon, Olympic National Park (in Washington state), and Alaskan islands.