Rocky Mountain Elk Cervus elaphus nelsoni
The Rocky Mountain Elk
The second-largest member of the deer (Cervidae) family, elk are herd animals, with herd sizes varying greatly depending on location, local population dynamics, and habitat, but can number into the hundreds, stretching to the thousands on some western winter ranges. Cows and calves comprise the majority of these herds, with bulls living either alone or in small bachelor groups until the rut, when they join the cow/calf groups for breeding.
Elk are vocal animals, communicating danger quickly and identifying each other by sound.
Calves make a high-pitched squeal, whose mother recognizes her calf by its voice. A sharp warning bark warns the herd of danger. Elk make a variety of chirps, mews, and miscellaneous squeals to communicate with each other. During the rut, bulls will “bugle,” a bellow escalating to a squealing whistle ending with a grunt, as a way to advertise its fitness to cows, as a warning to other bulls to stay away, or as a fight challenge to other bulls. Elk also use body language. For example, an elk displays dominance by raising its head high.
Prior to the rut in fall, individual herds may aggregate into large herds, which subsequently break into smaller groups as males seek out cow groups and form harems. A bull will wallow in mud to coat itself with a urine “perfume” to attract cows. They also bugle and rub trees, shrubs, and the ground with their antlers to attract cows and intimidate other bulls. A bull will aggressively guard its harem against other bulls — during the rut, typically small 2 ½-year-old and yearling males are expelled from the harem by large, dominant bulls — and groups of small, young, nonbreeding bulls may form, with lesser and younger bulls often circling the herd as they look for an opportunity to slip in and breed cows when the herd bull is distracted. Sometimes, bulls wage violent battles for a harem, occasionally even fighting to the death.
According to the well-known 2002 book, “North American Elk: Ecology and Management,” edited by Jack Ward Thomas and Dale Toweill, the oldest living bull elk in a non-hunted population was 14 years; the oldest living cow was 21 years. However, bull elk typically live less than 10 years in unhunted populations and less than five years in hunted populations.
Located in the Rocky Mountain west and adjacent mountain ranges from Arizona north into Canada from Ontario west, Rocky Mountain elk have been transplanted in recent decades too many of the elk’s historic ranges in states like Pennsylvania, Kentucky, Tennessee, Arkansas, Kansas, Nebraska, Texas, Virginia, West Virginia, North Carolina, Michigan, Minnesota, and Wisconsin. The total estimated population today is about one million. Estimates place the historic North American continent population at around 10 million.
Elk are tough and adaptable, and live in a variety of habitats, from rainforests to alpine meadows and dry desert valleys to hardwood forests, depending. They may inhabit the same range throughout the year or migrate to separate summer and winter ranges, with migratory herds generally found in mountainous regions, where the elk move up and down elevation or river drainages in response to weather and seasonal changes in vegetation. Winter ranges are most common in open forests and floodplain marshes in the lower elevations. In summer, elk migrate to subalpine forests and alpine basins. Transitional ranges are used in spring and fall as elk move between summer and winter ranges. Individuals generally retain the same ranges from year to year and travel the same routes between ranges. Elk have a diverse habitat range they can reside in but are most often found in forest and forest-edge habitats, and in mountain regions, they often stay in higher elevations during warmer months and migrate down lower in the winter. They may even come down the mountain and leave the forest into some grassland for part of the day but head back into the timber in the evening. They are most active early and late in the day, and at night.
An elk herd’s home range size varies greatly. A 2011 report issued by the U.S. Forest Service reported that elk home range sizes average from 1 to 95 square miles. Some of the largest reported elk home ranges were an average of 247 square miles for bulls and 149 square miles for cows in the White Mountains of Arizona. Generally speaking, home ranges are smaller when there is a greater abundance of forage. Adult bulls often have larger home ranges than cows in summer and appear to have less home range fidelity than cows. Also, cow/calf groups tend to occupy the center of the home range (where forage and water are most prevalent), with bulls living on the fringes.
- Bull: 700 lbs. average weight, 5 feet tall at the shoulder, 8 feet long nose to tail.
- Cow: 500 lbs. average weight, 4 ½ feet tall at the shoulder, 6 ½ feet long nose to tail.
- Calves: On average, weigh between 33-49 lbs. at birth, and 265 lbs. when weaned in spring.
- Antlers: A set of antlers of a large bull elk can weigh up to 40 lbs.
- Summer: Grasses and forbs. Spring and fall: grasses.
- Winter: grasses, shrubs, tree bark, and twigs. Elk may supplement their diet with licks, where they take in minerals that may help them grow healthy coats and produce nutritious milk.
An elk’s top two canine teeth are called ivories. Scientists believe ivories are remnants of saber-like tusks that ancestral species of elk used in combat.