E-Fauna BC: Electronic Atlas of the Wildlife of British Columbia

Oreamnos americanus Blainville
Mountain Goat; Rocky Mountain Goat; White Goat
Family: Bovidae
Species account author: David Shackleton
Extracted from the Hoofed Mammals of British Columbia

Photo of species

© David Shackleton  Email the photographer   (Photo ID #95472)

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Distribution of Oreamnos americanus in British Columbia.
(Click on the map to view a larger version.)
Source: Hoofed Mammals of British Columbia by David Shackleton © Royal BC Museum
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Species Information

The Mountain Goat is a moderate-sized ungulate with a stocky body, a noticeable hump above the shoulder seen in lateral profile, a thin neck, sharply pointed, thin black horns, and long, narrow pointed ears. The tail and lower limbs (metapodials) are short, and the hooves rather than being concave on the underside, have a thick, soft, rough-textured pad extending to the edge of the keratin hoof. The coat is completely white or yellowish white, but the nose, horns, hooves and dew claws are black. In winter, the coat consists of long guard hairs and thick underfur (wool) that are shed in June and early July for a shorter haired summer coat. Both sexes have a beard on the chin and a short mane along the underside of the neck, which is most obvious in winter. The long guard hairs on the upper two-thirds of the legs form noticeable chaps in winter. The interdigital glands are rudimentary, if present at all, and the lachrymal glands are absent, but there are black glands behind the base of each horn (the post-cornual or supra-occipital glands) that are larger in males than in females. The few weight data available for B.C. specimens suggest that females are 64 per cent lighter than males; but this may be misleading due to the small sample size. Based on the larger samples of body and skull dimensions, females appear on average about 12 per cent smaller than males in B.C., a figure more in line with sex differences reported for Mountain Goats elsewhere in North America.

Both sexes of Mountain Goat have short horns. Adult horns are usually 200 to 280 mm long, with the longest recorded measurement of over 300 mm. The horn sheaths are shiny black and sharply pointed with a smooth surface, except at the base. They diverge slightly as they curve upward and gently backwards from the head. In most males, the curve is smooth, while horns of many but not all females have a distinct bend near the tip. The horns of adult females, especially the bases, are noticeably thinner and further apart than those of adult males. The average anterior-posterior horn sheath diameter of five adult females was 33.3 mm (32–34 mm) while the average for seven adult males was 42.5 mm (36–48 mm). In rare instances, individuals may have one horn snapped off near the base, presumably the result of fighting or falling.

The skull is narrow in dorsal view, and its bones are generally fragile, especially in comparison with male wild sheep. There is no lachrymal depression in front of the orbit.

Biology

Identification

The Mountain Goat can be distinguished from all other ungulates in British Columbia by its characteristic all-white or light-cream-coloured coat, pointed ears, short beard and short black pointed horns. The only other all-white ungulate is the Dall’s Sheep, but its fur is much shorter in winter and its legs are slender and lack hair chaps. The horns of adult male Dall’s Sheep are much more massive than those of Mountain Goats. The horns of female and yearling male Dall’s Sheep are similar in size to those of Mountain Goats, but they are brown, ridged and blunt tipped, not black and pointed.

Some people still confuse Mountain Goats with female Bighorn Sheep where their ranges overlap, despite the different colour and the different horn and body forms. Bighorn Sheep have a brown coat, large white rump patch and a short black tail, in contrast, to the all-white Mountain Goat; and the horns of female Bighorn Sheep are brown and blunt-tipped in contrast to the thin, sharply pointed black horns of the Mountain Goat.

Mountain Goat skulls are distinguished from the most similar species (e.g., female and yearling male wild sheep) by the presence of sharp, black horns, the short, straight, sharp-pointed horn cores that, like the horns, are round in cross-section, and the much narrower cranium and orbital region. Like those of female and young male wild sheep, Mountain Goat skulls are quite fragile. The metapodials are characteristically short and robust, compared to those of wild sheep or Odocoilid deer of similar size. The soft pad of the Mountain Goat’s hoof is also unique among B.C.’s ungulates. Signs of Mountain Goats along trails are clumps of white hair they have left behind when shedding their winter coats.

Tracks of Mountain Goat are similar in size to those of Bighorn Sheep, Thinhorn Sheep, White-tailed Deer and Mule Deer. But the impressions of Goat hooves are more rounded at the tip than those of deer, and the individual hoof tracks tend to be narrower with more parallel sides than those of wild sheep. Distinguishing faecal pellets of Goats from wild sheep and even deer, is difficult.
Reproduction

After a gestation period of 147 to 178 days, young Goats are born in late May and early June. A female usually isolates herself in rugged terrain to give birth. Normally one offspring is born, but twins are not uncommon and triplets occur rarely. Shortly after birth, young Goats follow their mothers, who are highly protective of them. Mothers and young may form small nursery groups in spring, and even larger temporary aggregations in summer. Young Mountain Goats weigh between 2 and 3 kg at birth and are all white, like adults, although some young may have a brownish dorsal stripe from the neck to the tail that disappears before it is a year old. By the end of their first autumn, young have usually developed short black horns, 25 to 65 mm long, just slightly longer than the hair on their heads. The young Goats grow rapidly, but most yearlings are smaller than adults, and they have a concave facial profile. Typically, two year olds can also be distinguished from adults by their smaller bodies and horns, but not in populations living in good conditions. The horns of a yearling in spring and early summer are usually shorter than its ears, but by autumn the horns are as long as the ears; those of two year olds exceed ear length. Goats are usually sexually mature at 24 to 30 months of age. Most females probably bear their first young in their third year; males do not fully participate in the rut until they are at least five or six years old.
Diet

Mountain Goats are able to live on a wide variety of plant foods – grasses, forbs and much browse. The Mountain Goat’s wide food habits together with an ability to tolerate deep snow for short periods probably account for its widespread distribution throughout the province. For example, in the Coast Mountains, sudden heavy snowfalls can trap Goats for several days in shallow snow wells at the bases of mature conifer trees. The Mountain Goat’s ability to subsist on any available plant material means the difference between life and death.
Age determination and life expectancy

Unlike most other ungulates in the province, Mountain Goats show limited external sexual dimorphism. Horn shape is probably the best way to distinguish adult males from females at a distance; when viewing the animals close-up or examining a skull, the basal diameter of the horn is a more reliable indicator. Most adult female horns show a distinct change in curvature near the tip, whereas the curve of the male’s horns is smooth. Any animal seen to squat while urinating is almost certainly a female, and in short summer coat, a male’s scrotum is visible.

In spring, Mountain Goats can appear to be in poor condition, because large patches of their long coat are missing or hanging loose. This is normal and is simply a sign that they are shedding their heavy winter coats. Like many other species, pregnant and lactating females usually lose their winter coats later than other age-sex classes.

Mountain Goat age can be estimated by counting horn sheath rings (annuli). For animals older than about six years, this becomes difficult because successive rings are crowded together, especially in females. Also, the first ring, developed in the animal’s first winter, is usually no more than a smooth ridge that can be difficult to distinguish. The second year’s annulus is often the first easily recognizable ring. The emergence of permanent teeth and the replacement sequence of the deciduous teeth, can also be used to estimate age up to three years of age, and for older individuals, cementum annuli counts provide a reliable estimate.

Mountain Goats typically live around 10 or 11 years, with the oldest reported specimens being a 14-year-old male and an 18-year-old female.
Predators and other mortality factors

Not much is known about causes of mortality. Diseases (e.g., contagious ecthyma, white muscle disease) and parasites (e.g., wood ticks, lungworm) have been documented. The main predators of Mountain Goats are Cougars and Wolves; occasional predators are the Bobcat, Coyote, Wolverine, Grizzly Bear and Black Bear. Like wild sheep, steep cliffs provide Mountain Goats with essential security against mammalian predators, although the cliff habitat may be less useful against Golden Eagles which sometimes prey on young Mountain Goats. Eagles have been known to knock juveniles off cliffs, then swoop down to feed on them. Harsh winters also increase Mountain Goat mortality, and are especially hard on young animals, while avalanches sometimes take a toll on all ages. When being captured and handled for transplants or research, Mountain Goats can suffer from capture myopathy (often mistakenly called White Muscle Disease, which is a disease of Cattle and Domestic Sheep). As a result of stress induced during capture efforts, Mountain Goats may sustain muscle damage. In extreme cases, this can cause death at the time of capture, or afterwards because the animal is more susceptible to predation. In B.C., selenium is a mineral often in short supply, and low selenium levels in a Goat’s body may predispose it to capture myopathy.
Social organization, grouping and behaviour

Mountain Goats, primarily females and young, live in small groups of usually two to ten members, but sometimes in summer, larger groups are seen. Most often, the larger groups form in alpine meadows when feeding conditions are good. In some areas in B.C., more than 100 animals have been counted in these mother-young aggregations in summer. Outside the mating season, adult male Goats usually live alone or occasionally in the company of two or three other males.

Both sexes of Goats are aggressive by nature and their sharp, smooth horns are dangerous weapons. If fights occur during competition, both males and females can inflict serious wounds, and even lethal injuries on rare occasions. Mountain Goats seem to avoid fighting unless they have to. Instead, males use various threat and lateral dominance displays that may draw attention to their horns or body size. Their characteristic shoulder hump probably helps increase the visual effectiveness of the lateral display. When displaying laterally, a male will lower his head, tuck his chin between his forelegs, and with arched back, walk in a stiff gait, circling and pointing his horns at his opponent. This behaviour may encourage one of the males to leave, but if not, one or both may make upward, stabbing blows with its horns, usually at the opponent’s rear flank. The skin along the sides of the rump seems to be thicker, and may provide some protection against horn blows. Their characteristic aggressiveness and dangerous weapons, along with their preference for steep cliffs, may explain why their average group sizes are smaller than other mountain dwellers such as Bighorn or Thinhorn sheep. Besides a bleating sound audible at close quarters, both males and females make a variety of vocalizations, most often during aggressive encounters.

The social behaviour of Mountain Goats is poorly understood and our limited knowledge is based on a few studies. The timing of the mating season in British Columbia varies, depending partly on latitude; in some areas, mating begins in late October, but more often, it starts in early November and continues until mid December. During the rut, males rub their horn glands on bushes, and while it probably has some signal value, the function of this behaviour is unknown. During the rut, a male will also paw a depression in the ground, urinate in it, then rub his rear flanks in the wet dirt. Presumably, by covering himself with urine he increases his odour and so advertises his condition to females and rival males. In areas with dark soils, wallowing males develop dark patches along the flanks. Mountain Goats also wallow in summer; they do not urinate in the pits but roll in them for dust baths. They perform similar behaviour in snow patches in summer, possibly to reduce insect harassment or to stay cool.

A courting male will approach a female in a crouch, neck extended and nose pointed slightly upward, tongue flicking in and out. This is an extreme form of the more usual mating approach used by courting males of most other B.C. ungulates. The Mountain Goat male, however, must be especially careful when approaching an adult female, because she is all too ready to threaten him with her sharp horns. Once close to the female, he will nose her rear and flank, and gently kick her with a front leg. If she urinates, the male sniffs her and performs a lip-curl to test her reproductive condition. When the female is in full heat, she stands and allows the male to mount her, and she may even mount the courting male. Females are thought to remain in oestrus for 48 to 72 hours.

Habitat


Mountain Goats are remarkable climbers, able to scale extremely steep cliffs with obvious ease. Goats are found, especially in winter, in areas with steep rugged terrain such as cliffs and rock faces with ledges that they can travel along. Without doubt, they are the best climbers of all the ungulates in British Columbia, but contrary to some popular accounts, Mountain Goat hooves are not suction cups. Instead, the soft, rough-textured pads on the undersides of their hooves give them more surface friction than the hooves of other ungulates. These pads help the Goat climb on steep rock surfaces, while the hard keratin edges of its hooves help it cling to narrow rock ledges. The Mountain Goat’s climbing skills are further enhanced by the flexibility of the hooves, which can splay apart when necessary to increase their surface area. Finally, its heavily built front quarters probably help the Goat haul itself upward when climbing a precipitous cliff.

Mountain Goats most frequently occupy alpine and subalpine meadows, and steep forested slopes. In general, Mountain Goats, like many mountain ungulates, make seasonal migrations between high and low elevations. These movements are a response to seasonal changes in the availability of food, in snow accumulation patterns, and in microclimates. In winter, unless they can find south- or west-facing windblown slopes and ridges with sufficient food, Mountain Goats will move to lower elevations where the snow is not as deep and more food is available. In the Coast Mountains, where snow accumulations are very deep, Goats may be forced down to sea level. But in spring, when the snow begins to melt and forages grow again, the Goats move back to higher elevations. Summers are spent in alpine meadows, usually not far from rugged escape terrain, especially when predators are active in an area. Adult males in some areas, have been found to spend at least part of the summer at mid elevations in forested habitat, making them difficult to observe.

In some mountain ranges, Goats make heavy use of mineral licks during early summer, even when it means travelling long distances, sometimes through heavy timber, to reach them. Males in southeastern British Columbia appear to use licks earlier in the season than females do.

Distribution


Mountain Goats occupy all the major mountain systems of mainland British Columbia, but are absent from Vancouver Island and the Queen Charlotte Islands. Except for three isolated areas along the Nelson and Chief rivers, and Boat Creek west of the Rocky Mountains, they are also absent from the Interior Plateau and Peace River Lowlands. On the west side of the province, Mountain Goats inhabit the Hazelton Mountains, and are distributed discontinuously and in varying densities along the Coast Mountains from the Yukon border to the international border. In the northern half of the province, Mountain Goats inhabit the Cassiar, Omineca and Skeena mountain ranges, and the Rocky Mountains as far south as Mount Garbitt, north of the Pine River. Their distribution begins again in the Rocky Mountains south of the Pine River and extends along the mountains on either side of the Rocky Mountain Trench, including through the Selkirk, Monashee and Purcell mountains as far as the international border. Mountain Goats are found generally across the southern part of the province, including the southern Okanagan.

A total of 29 translocations involving 229 Mountain Goats from B.C. were made between 1925 and 1996. Of these, 93 Goats were moved to locations outside the province (79 to Alberta, 10 to Colorado, 44 to Washington), where they helped repopulate regions where the species had been extirpated. In 1924, four Mountain Goats were taken from Banff, Alberta, and introduced to an area along Shaw Creek on Vancouver Island. Given the problems created by Mountain Goats introduced to the Olympic Peninsula, Washington, it is probably fortunate that this introduction was unsuccessful on the island.

Some good locations to look for Mountain Goats are: the cliffs on the north side of the highway between Hedley and Keremeos; in Garibaldi and Cathedral provincial parks; Robson Valley in Mount Robson Park; along Highway 16 between Prince Rupert and Terrace; along Highway 37 between Stewart and Meziadin Junction; and on Rocky Ridge near Kitseguecla.

Taxonomy


Mountain Goats belong to the Tribe Rupicaprini (goat-antelopes) and are the only representatives of this group in North America. Other members of this tribe are the Serow and Goral that inhabit steep forested mountain slopes in southeast Asia, China and the Himalayas, and the Chamois of the major mountain systems of western and central Europe and northern Turkey. Goat-antelopes are considered to be the most primitive members of the Subfamily Caprinae.

Previously, biologists recognized several subspecies of Mountain Goat in western North America. Three occurred in British Columbia: Oreamnos americanus americanus ranging north from the international border, through the Coast Mountains as far north as the Skeena River, in the Selkirk and Monashee Mountains to the north loop of the Fraser River, and in the Rocky Mountains from the Crowsnest pass to the Pine River; O. a. columbiae in the northern half of the province north of the Peace and Skeena rivers; and O. a. missoulae in the Rocky Mountains south from the Crowsnest Pass. But since Cowan and McCrory’s 1970 review, Oreamnos americanus has been considered a monotypic species (i.e., with no subspecies). The type locality for the species is uncertain, but it is probably Mount Adams in Washington.

Fossil Mountain Goat specimens are extremely rare, probably because their skulls are quite fragile. It is also rare to find modern Mountain Goat skulls in the field because they weather and disintegrate quickly, or are broken by bears and wolves feeding on them. The earliest fossil of modern Mountain Goat in North America comes from Quesnel Forks, British Columbia, in interglacial deposits prior to the last glacial period (Wisconsin). These deposits are believed to have been formed more than 90,000 years ago. Recently, David Nagorsen of the Royal British Columbia Museum, has recovered remains of Mountain Goats from caves on northern Vancouver Island dating from about 12,000 years ago.

Remarks


The genus name Oreamnos is derived from the Greek ore for “mountain” and amnos for “lamb”, although Mountain Goats are neither sheep nor even true goats. The specific name americanus refers to the species’ geographic origin.

Handling Mountain Goats requires extreme caution. To avoid being injured by the sharp horns, wildlife researchers often push pieces of garden hose onto the tips when they capture an animal.

Mountain Goats are easily disturbed by low-flying aircraft, especially helicopters. Low-level flights stress the Goats, increasing the possibility of both indirect and direct mortality. Photographing or viewing Mountain Goats from low-flying aircraft, especially from helicopters, should be avoided; and heli-skiing operations need to take winter distributions of Goats into account. Helicopters should stay well away from alpine areas and cliffs used by Mountain Goats; one study recommended flying no closer than two kilometres. Researchers should also use caution when observing Mountain Goats, and especially when immobilizing and handling them. Recent research in Alberta suggests that Mountain Goats may be more susceptible to such activities than most other ungulate species, and that the impacts may be long-lasting.

Status Information

Origin StatusProvincial StatusBC List
(Red Blue List)
COSEWIC
NativeS3BlueNot Listed
BC Ministry of Environment: BC Species and Ecosystems Explorer--the authoritative source for conservation information in British Columbia.

Additional Photo Sources

General References


Recommended citation: Author, Date. Page title. In Klinkenberg, Brian. (Editor) 2021. E-Fauna BC: Electronic Atlas of the Fauna of British Columbia [efauna.bc.ca]. Lab for Advanced Spatial Analysis, Department of Geography, University of British Columbia, Vancouver. [Accessed: 2022-05-16 8:12:30 AM]
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