Oreamnos americanus
(Mountain Goat)

Order: Artiodactyla
Order Description: Hoofed Mammals or Ungulates
Family: Bovidae
Family Description: Goats and Sheep

Mountain goats are striking with their long, white hair that occasionally has a yellowish tan tone. In winter their hair appears long and shaggy, in summer it is shorter. Adults have long hair under their throat forming a “beard” that may be up to 5 inches long (125 mm). Both sexes have sharp pointed horns Click word for definitionthat curve up and slightly backward, in females they reach 9 inches (230 mm) in males about 12 inches (300 mm). Their hooves are well adapted to their living on cliffs and ledges, they have a hard, straight outer margin, with soft and flexible inner pads that provide excellent traction in their precarious habitat. They stand about 3 to 3 ½ feet (90 to 100 cm) at the shoulder and weigh between 100 and 300 pounds (455-135 kg). Females are about 15% smaller.

Mountain goats range from southeastern Alaska, south to Washington and the Olympic Peninsula, to western Montana and southern Idaho. They have been introduced in Colorado, Oregon, Olympic Peninsula of Washington, Beartooth Mountains of Montana, and South Dakota. Some Idaho populations were introduced outside historic range.

Environmental extremes characterize their habitat. They are found in high mountain alpine and subalpine habitat where extremes of temperature and weather occur. At various locations in their range they can be found from sea level to about 8000 feet (2440 m), but they are usually at timberline or above. They favor steep grassy or talus slopes, grassy ledges of cliffs, or alpine meadows. During the winter they may seek shelter and food in stands of spruce or hemlock. They seem comfortable on precarious cliff ledges and extremely steep, talus slopes.

Mountain goats graze on grasses and forbs Click word for definitionin summer, but also browse Click word for definitionon shrubs and conifers. Their winter diet is often variable; they may feed on mosses and lichens Click word for definition, as well as grasses, shrubs, and conifers.

They tend to be most active from dawn to mid-morning and late afternoon to evening. They move to more sheltered habitat in October and November when snow begins to fall, and back to high alpine habitat in April and May with the spring thaw. In Idaho, they may move up to 16 km in the winter to appropriate habitat which typically is the lowest suitable range on south-facing mountainsides. One Idaho band of 10 animals wintered in only 205 acres (81 ha). Males are solitary or in small male groups most of the year, but join the female and young groups in October or November prior to the rut Click word for definition. There is a strong social hierarchy in female groups; the dominant are females. Adult females and young form small groups in summer. Annual home range in different areas of Montana was reported at 6-24 km2. Because they are so inaccessible they have few predators. Golden eagles are known to take young, often by forcing them off of cliffs, and cougars are known predators as well. A major cause of mortality is accidents. Their habitat is dangerous even though they are so “sure footed”; they do occasionally fall and are injured or killed.

Mountain goats mate in November, but the rutting season can last into December and even January. Males do not butt heads as do Mountain sheep, but most of their rutting competition consists of threats, with occasional battles in which the males swipe their sharp horns at each other. Males have scent glands at the base of their horns, and will scent mark females they will breed with by wiping the side of their head on the female’s body. Gestation Click word for definitionlasts about 178 days. One (sometimes 2, occasionally 3) precocial young is born in late May or early June. Often young are born in a “safe” area consisting of a narrow ledge on a cliff or very steep slope; while this may seem dangerous for the newly born young, its location probably provides protection from predators. The young are very precocial Click word for definitionand can scamper after their mother with amazing agility. The young stays with their mother for a year until the next year’s young are born. Young are sexually mature in about 2 years, although in some areas some yearling females may breed. Young to female ratios vary between 39:100 and 72:100 were recorded in one Idaho study.

Status: Game species
Global Rank: G5
State Rank: S4

Important State References:
Hayden, J.A. 1989. Status and population dynamics of mountain goats in the Snake River Range, Idaho. M.S. Thesis, Univ. Montana, Missoula. 147pp.

Information written by Donald Streubel,© 2000
Map image provided by
Stephen Burton,© 2000
Design by Ean Harker©1999, 2000.