able from Dall sheep by their black horns. These creatures are well adapted for extreme winter conditions and have a long, shaggy winter coat. A crest of long, erect hair up to eight or more inches in length runs along the spine, on the rump, and over the shoulders and neck. Long hairs on the legs give the appearance that the goat is wearing pantaloons. Mountain goats begin shedding their winter coat in June, with adult males and sub-adults shedding-out before females. By July, their soft, sleek summer coat is grown in. When the first winter snows dust the high country in mid-October, mountain goats have fully grown their winter coats again.
The appearance of both sexes is much alike except that males are about 40% larger than females and have differently shaped horns. Adult female goats weigh about 180 pounds, with males averaging about 280 pounds (in late-summer); prime-aged males often weigh more than 300 pounds, with the largest male yet weighed topping 385 pounds. The horns of an average adult female are equal in length to those of an average adult male but are more slender and bend back more sharply at the tip. Mountain goat hooves are specially designed for climbing in steep, rock, and slippery terrain. A close-up look reveals a hard keratinous sheath and a soft embedded pad that enable goats to gain purchase on the smallest of granite cracks while simultaneously gripping maximum surface area.
Growth and Reproduction
The breeding season for mountain goats occurs between late October and early December. Billies (males) may travel considerable distances in search of receptive females (nannies). Mountain goats have a polygynous mating systems, meaning that males will breed with multiple females but not vice versa. Typically, prime-aged males (5-10 years old) do most of the breeding, with some battling among males causing occasional horn-inflicted puncture wounds. Adult males usually separate themselves from larger nanny-kid nursery groups except for during the rut. They may form small bachelor groups, especially in summer. Females, on the other hand, tend to stay in groups along with kids and immature animals. This behavior is particularly evident during mid-summer when large nursery bands form.
Usually a single kid is born in mid-late May after a gestation period of approximately 180 days. Twinning occurs rarely. Nannies seek out rugged, isolated sites prior to giving birth but soon join other nannies with newborn kids to form nursery groups. Kids remain with their mothers until the next breeding season and often for some years beyond. Interestingly, mountain goats will not give birth until they are 4 years of age; this is quite old compared to female moose, black-tailed deer, and caribou. Mountain goats may live up to 18 years, but most live less than 12.
Mountain goats are both grazing and browsing animals depending on the particular habitat and season of the year. They normally summer in high alpine meadows where they graze on sedges, forbs, and low-growing shrubs. As winter advances, feeding habits generally shift to browsing. Blueberry, hemlock, and lichen can be important winter diet items, but feeding habits in winter center on availability.
Range and Habitat
Mountain goats occupy remote habitat and are therefore the least studied large mammal in North America. The mountain goat’s range is restricted to the steep and broken mountain ranges of northwestern North America, from the northern Cascade and Rocky mountains to Southcentral Alaska. In Alaska, mountain goats occur throughout the southeast Panhandle with their range continuing north and west along the coastal mountains to Cook Inlet. In Southcentral Alaska they are generally confined to the Chugach and Wrangell mountains, although small numbers of goats have been documented in the Talkeetna Mountains. Mountain goats have also been introduced to non-native range on Kodiak and Baranof Islands where populations have expanded, on Chichagof Island where the transplant apparently failed, and most recently on Revillagigedo Island where goats are now firmly esta