Elk of Yellowstone National Park

Elk are the most abundant large mammal found in Yellowstone National Park and have been living in the Yellowstone area for at least 1,000 years. More than 30,000 elk from 7-8 different herds summer in Yellowstone and approximately 15,000 to 22,000 winter in the park.

Elk have an acute sense of smell, excellent eyesight, and can live as long as 15 years. Elk calves are usually born in early June and have lost their spots by early autumn.

Adult males (bulls) weigh an average of 600-700 pounds while the females (cows) average around 500-525 pounds. Measured from nose to tail, elk can be anywhere from 7 to 10 feet in length and stand 4-1/2 to 5 feet tall at the shoulder.

Bulls grow antlers annually beginning when they are about one year old. Antlers of a mature bull may have 6 to 8 points or tines on each side, weigh more than 30 pounds, and reach as wide as 5 feet.

Bull elk shed their antlers in early spring. Regrowth begins in May, when the bony growth is nourished by blood vessels and covered by furry-looking "velvet." Antler growth ends each year by August. The velvet dries up and bulls begin to scrape it off, rubbing their antlers against trees, in preparation for the autumn mating season or "rut."

Bull elk use their legendary bugling calls to challenge the other bulls and attract cows. A bull may gather 20-30 cows into his harem during the mating season, often sparring with other mature males for the position of dominate male in the herd group. Mating season ends by November and the elk herds generally move to their winter ranges.

Elk wear a double-layer winter coat during the cold months: the long guard hairs on top keep them dry, and a soft woolly undercoat keeps them warm. In late spring elk shed their winter coats and grow a single-layer summer coat that's sleek and copper-colored.

Elk are members of the deer family and are herbivores. They eat only plants including grasses, forbs (low-growing, short-stemmed plants), shrubs and trees (including limbs and bark). Elk must eat and watch for predators at the same time, so they gather in herds where at least one animal is looking up while the others are eating. Even while feeding, Elk constantly twitch and turn their ears to listen for sounds of trouble.

Although elk are usually found in mountainous and forested terrain, they are also well suited to open spaces. Elk have strong hearts and lungs, and long powerful legs designed for speed and endurance.

Climate is the most important factor affecting the size and distribution of elk herds in Yellowstone. Nearly the whole park provides summer range for elk. However, winter snowfalls force elk to the northern, lower-elevation portion of Yellowstone. Here the temperatures are more moderate and, with less snowfall, can support large numbers of wintering elk.

Elk are mostly active at dawn and dusk, so early morning and late evening afford the best opportunity for seeing elk in the park (or in the wild, for that matter.) Elk may sometimes be seen feeding during the day, if the temperatures are mild, and the area is quiet and undisturbed.