Greater Yellowstone Mountain Goat - Oreamnos americanus
The Mountain Goats of the Greater Yellowstone eco-system make a home on the vertical planes of the Rocky Mountains where they cling and move around on the impossibly steep slopes of this unforgiving and barren terrain, Mountain Goats can survive on scant food in incredibly hostile environs. Mountain goats fit perfectly into the category of "charismatic mega-fauna." Their beauty, grace, and athleticism, is a treat to watch and their cute faces are always a thrill to see. The kids are precocious, able to move on steep slopes within hours of birth, an awe-inspiring site in itself.
Although the Yellowstone Ecosystem has an abundance of Mountain Goat habitat, Goats are not endemic to the region. Between the 1940s and the 1960s, there were several hundred of the shaggy cliff dwelling creatures transplanted from western Montana to the Beartooth, Absaroka, Madison, Bridger, and Crazy mountains and the Snake River Range. Hundreds of them now inhabit the high country. Some of those animals are willing to leave their preferred high-elevation habitat to cross rivers, and valleys too colonize new places. There haven’t been any transplants in the Gallatin Range, for instance, but goats thrive there today.
Wyoming, Idaho and Montana are ecstatic about having mountain goats grace their mountains; however, Yellowstone Park is not. The problem is; they aren't native to the Yellowstone region. Mountain goats are considered an exotic/non-native species to Yellowstone National Park, and our national parks are managed to keep things as close to their natural state as possible. The Mountain Goat does not qualify.
The mountain goat population in Yellowstone National Park is firmly establishing itself. They are thriving in the mountain ranges surrounding Yellowstone as well. Park Service policy disapproves of the introduction of non-native species of any kind and calls for Mountain Goats to be managed; "up to and including eradication" if goats threaten park resources it is policy that control is "prudent and feasible." Hopefully, these acrobats of the heights will not wear out their welcome! It is estimated Yellowstone has enough suitable habitat to sustain up to 300 goats.
Mountain Goats are perfectly suited for their vertical world, some adaptations that help a Mountain Goat to survive is its horns, jumping ability, their cloven hooves, and teeth. Their horns help to defend them from predators. Mountain Goats have great strength in their hind legs enabling them to jump great distances when needed. Their hooves have a slit in the middle to make them more flexible. They get most of their water from their food.
Mountain Goats have an off white long shaggy, their coloring is off-white, and their fur is very fluffy. They have a beard under the chin and furry pantaloons skirting their front legs. Mountain Goats weigh about 100 to 200 pounds and their body is compact and chunky, old billies may weigh 300 lbs. They are 4.5 feet long, and their shoulder height is about 36 to 48 inches. The females are smaller than the males by almost 30%, their legs are about 20 inches long, their black cloven hooves have hard outer edges with soft centers that stick to rocks; Their hooves are adapted to the rugged slopes by being flexible, like rubber, so they can jump from rock to rock. Their horns are smooth and sharp that curve slightly backward and are 8-12 inches long; horns of nannies curve less and are thinner, but sometimes longer, than those of billies;
Mountain Goats breed annually between November and January. Gestation periods last 150 to 180 days and their kids are born in the spring. When a nanny is ready to give birth, she hides in the cliffs of her home territory so that she will be safe from predators. The kids are very independent as soon as two weeks after birth. Kids are weaned at 3 to 4 months, but they stay with the nanny until she reproduces again the following spring. Both billys and nannies reach sexual maturity after 30 months. One to two weeks after birth nannies and kids rejoin other females and young in small nursery herds on summer ranges. Kids remain with their mothers through winter, benefiting from their mother’s social status and access to foraging sites.
Mountain goats live in big groups in the winter, and smaller groups, or alone in the summer. The male goats are dominant during breeding season, however during the rest of the year season, the adult females take over that role. Mountain Goat hierarchies are determined early by the kids' playing behavior. The stronger more dominant kids become the leaders of their group.
The Mountain Goats' range changes from season to season. They migrate between lowland winter areas, and high elevation summer ranges. They move to a 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. For winter, goats may move up to ten miles to the lowest suitable range on, sunnier, south-facing mountainsides. Nannies, during tough winters, often defend foraging locations to the exclusion of their kids. As a result, yearling mortality can be high during severe winters.
Because Mountain Goats are so inaccessible they have few predators. Eagles are known to take young, often by forcing them from cliffs, and mountain lions are known predators as well. A major cause of Mountain Goat mortality is accidents. Their steep mountain home is dangerous although they are sure footed; they do occasionally fall and are injured or killed.
Goats can be seen on Sepulcher Mountain, outside Mammoth Hot Springs, on the mountains of the Beartooth Scenic Highway, on the cliffs on the west side of hwy 89 one to three miles north of Alpine Wyoming and south of Jackson Hole, on Bliss Pass which is north of Slough Creek campground, and on Upper Barronette Peak located in the north east corner of Yellowstone Park. They are often seen on Palisades Creek Trail and Big Elk Creek Trail in Swan Valley Idaho.