Similar to the Rocky Mountain mule deer, the elk did not make a broad appearance on the North American scene until after the megafaunal extinctions, 10,000- 12,000 years ago. Prior to the extinctions, the elk only ranged as far south as Alberta, Canada. With ecological niches vacated by the extinction of the horses, shrub oxen, woodland musk ox, giant fugitive and stilt-legged deer, camels, mammoths, and mastodons, the elk was able to colonize nearly every corner of North America, the only exceptions being the hottest and driest deserts of the Southwest and the hot swamp forests of the Southeast.

North American elk (Cervus elephus), also known as wapiti, comprise several subspecies, the most common being the Rocky Mountain elk (Cervus elephus canadensis), which is the subspecies native to Colorado and the Uncompahgre Plateau. It once extended from the northern prairies as far as Alabama, the Carolinas, and Georgia. Other subspecies include the Tule elk of the grasslands of the California’s Central Valley, Roosevelt elk of the Pacific Northwest, and Merriam’s Elk of the Southwest, which is now extinct.

Elk tend to be highly migratory in the western United States, the autumn movements typically being to lower elevations to avoid snow cover. They are also highly gregarious, with herd size varying with the seasons. Following calving in the late spring, mother and newborn tend to remain alone for several weeks. Shortly thereafter, cows and their young begin to amalgamate. By mid-July, herds as large as 400 may congregate, led by mature, older cows. Mature bulls tend to remain alone or in groups of up to 6 during this time. As the rut begins in September, bulls tend to gather harems of 15-20 cows each. After mating is completed, usually by late October, bulls once again separate from the female groups. As winter advances, herds of up to 1,000 animals may aggregate on winter feeding ranges.

The diet of elk varies throughout the year, but on the whole elk tend to exhibit a grazing rather than a browsing foraging habit, though browse is an important component of their diet at certain times of the year. In the spring, up to 85% of daily intake is comprised of grass. In the summer, a shift to more forbs and woody plants occurs, while browse and dried grass is preferred in the autumn. In winter, shrubs and conifers may become an important diet component, especially during times of deep snow cover.

Elk were reduced to only 41,000 individuals by 1900, but subsequent conservation measures have resulted in a recovery to nearly 800,000, and many populations are now subject to legal sport hunting. About 100,000 are killed each year.

Sources: Geist, V. 1998. Deer of the World. Stackpole Books. Nowak, R.M., ed. 1999. Walker’s Mammals of the World, Volume 2, Sixth Edition. The Johns Hopkins University Press.