See More: Deer

Elk | Mule Deer | White-Tailed Deer

“When do the deer turn into elk?” That’s not a joke waiting for a punch line. It’s a question that tourists often ask the rangers at Colorado’s Rocky Mountain National Park. The answer, of course, is that mule deer and elk are distinct species within the family Cervidae, which also includes the smaller white-tailed deer. But even for experienced hikers who realize that deer don’t undergo a metamorphosis, these three antlered ruminants can look similar from a distance. Here’s how to tell them apart.

Elk

Cervus elaphus

Larger than all other deer species except moose, bull elk can reach 700 pounds.

More than one million elk populate the western United States and Canada. Elk in the East are actually herds of Rocky Mountain elk reintroduced in the 1900s.

Elk move in large herds where open woodlands meet grassy meadows. After sheltering in forested valleys during winter, they climb to higher elevations in spring and summer for better browsing.

During the fall rut, when bulls battle to collect a harem of females, listen for bugling at dawn and sunset. The resonant honk can carry for miles–and ends in a high-pitched squeal.

Listen for bugling, or look for tree bark scrapes about five feet high. That’s where male elk rub their antlers to shed the velvet in late summer.

Antlers

Large and heavy appearance, with rearward flare 4 feet wide; 1-8 forking tines per antler

Rump

Light-colored rump patches; 4- to 7-inch-long tail

Coat

Reddish, tawny-brown torso with dark brown head, neck, and snout

Elk | Mule Deer | White-Tailed Deer

Elk | Mule Deer | White-Tailed Deer

Mule Deer

Odocoileus hemionus Large, rotating, mule-like ears give these stocky, midsize deer their name.

This highly adaptable ungulate is found in every state west of the Mississippi, mostly in semi-arid woodlands and chaparral.

Mule deer establish distinct home ranges where forests border grasslands. These edge zones provide good foraging for green leaves, twigs, acorns, and berries.

Rather than run, mule deer escape by bounding on all four legs. This tactic, called stotting, helps them quickly switch directions and navigate rocky terrain.

Look for matted-down grass circles the size of a bathtub where mule deer rest during the heat of the day.

Antlers

Tines fork in a V-shape; a mature rack can spread to a 3-foot width

Rump

Small, white rump patch;

4- to 8-inch black-tipped tail

Coat

Stocky, gray-brown body is marked by dark forehead and white muzzle

Elk | Mule Deer | White-Tailed Deer

Elk | Mule Deer | White-Tailed Deer

White-Tailed Deer

Odocoileus virginianus

Weighing between 110 and 250 pounds, white-tails are smaller and shyer than other deer.

As many as 20 million white-tails inhabit most of the Lower 48 with the exception of California, Nevada, and Utah. Subspecies exist in Arizona, Oregon, and New Mexico.

Able to thrive everywhere from conifer and deciduous forests to swamps and farm lands, these skittish animals prefer open country with adjacent forests for protection.

They flash the white underside of their tails when startled, hence the name. Acute senses alert them to predators, which they outrun by sprinting and leaping.

Even humans can detect the musky, gym-socks scent that bucks rub on trees or scrape on the ground during the fall breeding season.

Antlers

Heart-shaped rack curves forward; tines branch (not fork) from main beams

Rump

Tan 6- to 10-inch-long tail with white underside

Coat

Fur turns from red-brown in summer to dull gray in winter; white belly and throat

Elk | Mule Deer | White-Tailed Deer