Mountain goats (Artiodactyla: Bovidae: Oreamnos americanus) are large herbivorous mammals that inhabit mountainous regions from southeast Alaska through the northern Rockies. In spite of their common name these aren’t true goats (members of the genus Capra), and may be better described as goat-antelopes. Both sexes have thick white coats of hair and thin black horns that curve backwards. Unlike deer they don’t shed their horns, and annual growth rings can be used to determine an individual’s age.
These animals exhibit seasonal migrations between high and low elevations. Throughout the summer individuals are often found alone or in small groups at high elevations, sometimes up to 13,000 feet (nearly 4,000 m). By late summer males begin to compete for females. Instead of butting heads like bighorn sheep, males stab at each other’s sides with their horns. Although thick skin helps protect them, they are capable of injuring and killing one another. By autumn groups of females congregate and accept dominant males, and together they slowly make their way to lower elevations. Greener, relatively snow-free meadows provide sufficient food through the colder months, as well as relatively safe environments in which to breed.
Mating occurs from November through January, and from May through June females are ready to give birth. They migrate back to higher elevations where steep rocky slopes help protect their young from predators. Their main threat comes from mountain lions, but grizzly bears, wolves, and eagles are also capable of killing young, sick, or old goats.
The natural range of mountain goats has been artificially expanded southward through human introductions. In Olympic, Yellowstone, and Rocky Mountain National Park these animals are considered invasive and are sometimes killed to protect local ecosystems. In these areas mountain goats are undesirable since they can decimate native plant species and introduce diseases to threatened bighorn sheep populations.