High up in the alpine of Colorado’s Rocky Mountains, the surrounding views of mountain peaks are vast, and wild tundra grasses coat the ground with tiny wildflowers. Mountain goats scramble up and down rocky outcrops on sure-footed hooves, unaware of the controversy their existence stirs.
The mountain goat (Oreamnos americanus) thrives in mountainous areas throughout western North America. As herbivores, they enjoy grazing for grasses, mosses, and lichens; and delight upon the leaves and twigs of the few shrubs and conifers hardy enough to grow at such high altitudes. Come winter, they make their way to lower elevations, where food and mineral licks are easier to find.
Much like other members of the Bovidae family—gazelles, antelopes, and cattle—mountain goats prefer to live in herds, where a specific hierarchy has been observed. Mountain goat kids, who begin climbing rocky slopes (clumsily) within hours of birth, are typically born between late May and early June. For the first year of their lives, kids closely follow their mothers (called nannies), who protect them from predators.
It’s believed mountain goats originated in the Himalayas and made their way to North America when their ancestors crossed the Bering Land Bridge as part of the Pleistocene Megafauna migration. Fossils discovered in a Pleistocene fossil site, near South Park, called Porcupine Cave indicates a species of mountain goat called the Harrington’s mountain goat (Oreamnos harringtoni) lived in Colorado as far back as 800,000 years. This species disappeared following the massive animal extinction event at the end of the last ice age (Pleistocene epoch) 11,700 years ago.
So where did the mountain goats wandering the Rocky Mountains of Colorado in the modern day come from?
According to the University of Colorado Boulder’s Colorado Art and Sciences Magazine, the goats were introduced from Montana in 1947 and again in 1972.
In their new home, the species thrived. At the request of the International Order of Mountain Goats in 1993, the Colorado Wildlife Commission declared the mountain goat a native species—a controversial decision.
Biologists say the introduced mountain goats are not a native species. They worry about their impact on our native herbivores, like bighorn sheep, with whom the mountain goats’ food and habitat usage overlaps. Concerning observations of interactions between the two species indicate mountain goats are often dominant to bighorn sheep. As mountain goat populations increase, bighorn sheep populations decline.
Botanists have sounded the alarm bell as well. At Summit Lake on Mount Evans, the fragile Arctic habitat, which was designated a natural National Landmark, has been threatened by the colonization of mountain goats. They trample the permafrost and overgraze the rare botanical species.
Other states in the West have experienced similar problems from non-native mountain goats. Unlike Colorado, some have implemented controversial measures to control the goats’ ballooning populations.
In Wyoming’s Grand Teton National Park, the National Park Service in 2020 began culling mountain goat herds by shooting them from helicopters. This likely sounds grim to animal lovers, but biologists argued that if decisive human action wasn’t taken, troublesome herds would decimate native bighorn sheep populations.
Unfortunately, there is no easy answer.
