Mountain goat

Name and taxonomy

The French zoologist Blainville described the species in 1816. An earlier name, Ovis montanus, came from Ord in 1815 and treated the animal as a sheep. The type locality was later fixed at Mount Adams in the Cascade Mountains of Washington. The genus name Oreamnos joins two Greek words, one for mountain and one for lamb. Some writers read the first part as a reference to a mountain nymph instead. The species is the only living member of its genus.

English speakers also call it the Rocky Mountain goat, the white goat or the snow goat. The German and Dutch names translate as snow goat, and the French call it the goat of the Rockies. It sits in the family Bovidae, with cattle, antelopes and gazelles, and in the subfamily Caprinae. That subfamily also holds the true goats, the wild sheep, the chamois and the muskox.

Evolution and relatives

The goat-antelope group arose in the Late Miocene, and most of its lines still hold a species from the eastern Himalaya. So the ancestors of the mountain goat probably lived somewhere between Tibet and Mongolia. Its line split from its relatives about 7.5 to 8 million years ago. The takins of the Himalaya evolved in parallel from a similar ancestral goat and remain close relatives. Sheep are also close, while the muskox line stands further away. Its ancestors probably crossed the Bering land bridge into North America before the last glaciation.

The fossil record is short and comes only from North America. A smaller species, Oreamnos harringtoni, once lived further south in the Rockies during the Pleistocene. Ancient DNA shows that it was a sister species rather than an ancestor. One handbook notes that the exact position of Oreamnos among the Caprini remains unclear.

Appearance

The coat is white, sometimes with a little brown along the back, and it grows thick and shaggy in winter. It has two layers: a dense woolly undercoat and an outer layer of long hollow hairs. This coat lets the animal stand winter cold of minus 46 degrees Celsius and winds of 160 kilometres per hour. A ridge of longer hair runs along the spine, and both sexes have a beard on the chin. The goats moult in spring by rubbing on rocks and trees, and pregnant females shed last. The horns are black, slender and slightly curved, and they measure 15 to 28 centimetres.

The horns are never shed, and each year adds a growth ring that shows the animal's age. A male's horns curve back more strongly and are thicker at the base. Head-and-body length is 120 to 179 cm, and the tail adds 10 to 20 cm. Males weigh 61.4 to 81.8 kg and females 56.8 to 70.5 kg, by the Animal Diversity Web figures. Other accounts put large males at 95 to 115 kilograms, up to 30 percent more than a female. Telling the sexes apart in the field is hard all the same.

The hooves are large and oval, with a hard rim and a soft, rubbery inner pad that grips rock. The two toes spread apart on rough ground, and sharp dewclaws stop a slide. Strong shoulder and neck muscles push the body up slopes steeper than 60 degrees. Black scent glands sit at the base of the horns.

Habitat and range

The native range runs from southeast Alaska and the southern Yukon through British Columbia and Alberta. It continues south into Washington, Idaho and western Montana. Whether the species was ever native to Oregon is not settled. People have moved goats into Colorado, Utah, Nevada, Wyoming, South Dakota and the Olympic Peninsula. Introduced herds also live on Kodiak, Chichagof and Baranof islands in Alaska. The northern limit of the range is thought to lie in the Talkeetna Mountains of south-central Alaska.

The goats live in a patchwork of alpine meadows, ridges, scree and bare cliffs. Cliffs are escape terrain, and in winter the herds stay within 300 to 500 metres of them. Elevations range from sea level on the coast to above 4,000 metres. Most herds stay above the tree line all year, but they move up and down the slope with the seasons. In winter they favour snow-free slopes that face south or west, close to the tree line. Spring trips to mineral licks can take a herd several kilometres through forest. In the Cascades the goats occur mainly at 600 to 2,400 metres.

Diet and feeding

The mountain goat is a herbivore and a grazer for most of the year. Across its range the summer diet is about 52 percent grasses, 30 percent forbs and 16 percent browse. In winter browse rises to about 32 percent, and conifer twigs become a large part of it. Sedges, ferns, mosses and lichens fill in where grass is scarce. In South Dakota mosses and lichens made up 60 percent of one winter diet. In Colorado captive animals ate mostly forbs in both seasons, so no single figure fits every herd.

The goats take most of their water from plants and from snow banks that last through summer. In spring they walk many kilometres to natural salt licks for minerals. Where licks are absent, as in the Olympic Mountains, they lick human sweat and urine for the salt. In summer they feed in six or seven bouts a day and rest between each. Zoo animals also accept grain, alfalfa, fruit and vegetables.

Behaviour and social life

Group size changes with the season. Herds are largest in winter and at spring salt licks, and smallest in summer. Nursery groups hold females, kids and one- and two-year-olds, and can pass 100 animals in summer. By late autumn most nursery groups shrink to under 30. Adult males live alone or in small bachelor bands and keep apart from the females. Outside the rut, adult females dominate every other age and sex class, including the males.

Females form a linear hierarchy, and age decides rank, not horn size or weight. They compete hard for space and food. Two rivals circle each other with heads low and horns displayed, and most bouts end without contact. A goat that wants to avoid a fight stretches low to the ground. Kids sort out their first ranks through play. The goats scrape shallow beds, 25 to 50 millimetres deep, and rest in them at midday and at night.

They also dust-bathe in these beds, which may help them shed parasites and loose hair. They are most active in early morning and late afternoon, with some feeding at night. Daily movement stays on one mountain face or one basin. Summer home ranges are about 23 square kilometres, and winter ranges are much smaller. Some radio-collared goats in British Columbia used winter and summer ranges 8 to 13 kilometres apart. In 2021 a goat in Yoho National Park killed a grizzly bear with its horns.

Communication and senses

Mountain goats are mostly quiet, and most calls come in the mating season. Like other bovids, a mother and her kid probably keep contact with soft bleats. Posture carries most of the message. In a present threat the goat turns broadside and arches its back to look bigger. A horn threat swings the horns at a rival, and a rush threat is a sudden charge. A walking version, the orientation threat, is the mildest form.

Almost all of this is bluff, and injuries are rare. A courting male approaches low, shows the side of his face and beard, licks the female's coat and kicks her flank. The scent glands at the horn base probably mark rocks and rivals, as in other goat-antelopes. Like most hoofed prey, the goat seems to rely on sharp eyesight to spot a predator far below.

Reproduction and life cycle

Courtship begins in September, when males try to join small bands of females. A male digs a rutting pit and rolls in it, so his coat turns dirty and marks him out. Mating peaks in November and December, and the females in a herd come into season together. Mature males stare at females for long spells, dig pits and fight in showy but sometimes dangerous bouts. Rivals do not clash head to head but stand side by side and stab at each other's flanks. Thick skin on the flanks limits the damage, but deaths from chest and neck wounds are known.

Both sexes usually mate with several partners, though a dominant male tries to guard a female in oestrus. Gestation lasts about 185 to 195 days, and kids are born in late May or June. The female moves to a lonely ledge to give birth, licks the kid dry and eats the afterbirth. Most births are single, twins are rare, and triplets are on record. A newborn weighs a little over 3 kilograms and tries to run and climb within hours. It stays hidden for about a week until it can follow its mother across rough ground.

Weaning comes at 90 to 120 days, but the kid follows its mother for a full year. She stands over it when a predator appears and walks below it on a steep slope to break a fall. Both sexes mature at about 30 months, but females at Caw Ridge in Alberta first gave birth at four or five. At Caw Ridge 87 percent of kids reached weaning and 64 percent reached one year. Wild goats usually live 12 to 15 years, and the oldest known female reached 18. Zoo animals live 16 to 20 years, and one reached 20.8.

Predators and threats

The cougar is the main predator, because it can kill an adult and can follow one across rock. Wolves, wolverines, lynx, coyotes and both bear species take goats when they catch them on gentler ground. Golden eagles and bald eagles sometimes carry off a newborn kid. One wolf killed a yearling female in 1995, but soon after a mother drove an adult wolf off her kid. Such defence is rare, and one study in 2006 recorded only 5 cases. Steep cliffs are the real defence, and a goat that stays on the rock is hard for any bear to reach.

Avalanches are a major killer, and in Alaska they cause 23 to 65 percent of deaths, depending on the region. Ticks and chewing lice live on the coat, and tapeworms and lungworms live inside. Unregulated tourism, mining, oil and gas work and clear-cut logging disturb herds outside protected areas. Roads and other building split the range into pieces. Herds cope poorly with hunting that takes females, so managers set cautious quotas.

Population and conservation

The IUCN lists the mountain goat as Least Concern. One estimate puts 75,000 to 110,000 animals in North America. British Columbia holds 36,000 to 63,000 of them and Alaska 24,000 to 30,000. Numbers have stayed fairly stable, and the species is in no danger of extinction. Some herds are falling, such as those in the Cascade Mountains of Washington, where hunting is closed. Biologists there fit goats with GPS collars to learn why the herds are shrinking.

Introduced herds bring a different problem. In the Olympic Mountains, goats released in the 1920s trampled rare alpine plants and pestered hikers for salt. After one goat killed a hiker in 2010, the park removed hundreds, mostly by capture and release in the Cascades. Yellowstone allows controlled hunting to keep its introduced goats in check. Managers now advise caution before releasing goats into new alpine areas.

Relationship with humans

The mountain goat has never been domesticated. Pacific Northwest Coast peoples gathered the wool that wild goats shed on rocks each spring. They spun it into yarn and wove it into Chilkat blankets and other ceremonial textiles. Northwest Coast nations also hunted the goat, and many treated it as a sacred animal that gave itself as food. Today the goat is a prized trophy, and the hunt is hard because of the terrain. Hunting is closed where herds decline and allowed under quota elsewhere.

Visitors watch goats in national parks such as Kenai Fjords in Alaska. The goat is usually shy of people, but it is not harmless. Habituated goats crave the salt in human sweat and urine and approach hikers closely. The 2010 death in Olympic National Park shows what a horn thrust can do. Introduced goats in Olympic and Yellowstone also destroy native plants and may carry new diseases to native animals.

In culture and myth

The mountain goat appears in the stories of the Northwest Coast nations more than anywhere else. In several traditions it counts among the animals that gave themselves to people as food, so hunters honoured it with rituals. Certain tribes place the goat in the sky, and others treat it as a guardian spirit. Its wool in a Chilkat blanket gave the animal a place in ceremonial dress. Lewis and Clark saw the animal on the Columbia River, and Ord named it as a sheep from their reports in 1815.

Spirit-animal writers read the goat as a sign of balance, sure footing and persistence. These are modern blog claims and probably reflect the animal's climbing rather than any old tradition. Old World goat symbols, from the Capricorn of the zodiac to the sun and rain goats of ancient Iranian pottery, belong to other species. The name still confuses people, since the animal is a goat-antelope and not a goat.