Mule Deer

Mule deer at sunset.

NPS Photo

 

A mule deer doe with big ears.

NPS / Jared

Theodore Roosevelt National Park is a mosaic of badlands and prairie. Small mammals like the red squirrel and porcupine are often seen in forested areas, along with larger mammals, like mule deer and elk.

Mule deer, while closely related to white-tailed deer, are remarkably distinct in their biological, ecological, and behavioral attributes. Mule deer evolved in the dry, rugged badlands and mountains of the west. They have a distinctly different gait from the leisurely, graceful leaps of white-tail. When startled, a mule deer will move in a series of stiff-legged jumps with all four feet hitting the ground together. This gait (referred to as “stotting”), is believed to advantage deer while fleeing predators by allowing it to see over thick vegetation. It also allows the deer to out-distance predators in rough terrain, and to see above the thick brush. If necessary, they can turn or completely reverse direction in the course of a single bound.

Other characteristics that distinguish mule deer from white-tailed deer are their large ears (for which they were named), their larger body size, the form of the antlers, and their tail. A mule deer’s tail is thin and black-tipped, unlike the bushy white tail of its cousin.

 

Mule deer bucks with antlers in velvet

NPS Photo

Antler growth begins in the spring for male mule deer. Antlers are a true bone, covered with "velvet," a soft, skin-like tissue that carries nutrients and calcium for the rapidly growing antlers. During this growth period, a main beam will form, with “tines” growing vertically from it. Mule deer antlers are distinct from whitetail antlers due to their second tine forking into a “Y.” . Once the antler growth is completed in late summer, the blood-supplying velvet is no longer needed and begins to fall or get rubbed off. This leaves the antlers shiny and hard. Late each winter the antlers fall off and next spring the growth cycle begins again.

Antlers dropped during the winter provide an important source of nutrients for wildlife in the area. Mice, porcupines, coyotes, bison, elk, deer, and many other animals will chew on the the antlers throughout the year to absorb calcium and other minerals. Such a supplemental mineral source may be especially important during the birthing seasons of these mammals.

 

Mule deer doe and fawn.

NPS Photo

Mule deer breed in late November and early December. Mule deer bucks will cruise around the Badlands during this timeframe looking for receptive does. A buck will find a suitable doe and they will often play chase games at breakneck speeds before mating. They will remain together for several days.

Fawns are born in late May or early June. A doe will usually produce a single fawn, but when in good health having twins are not uncommon. Fawns can walk within a few minutes after being born. They have white camouflage spots and are further protected by having little or no scent. Fawns usually stay with the doe for the first full year.

 

During the summer, the deer feed on tender branch and leaf tips of trees, shrubs, and some grasses. They are crepuscular feeders and are most often seen in the early

morning and late evening. Mule deer are found in the West from Canada to Mexico and in a variety of habitats from the high mountains to the plains and deserts. In the South Unit, visitors typically don’t need to travel far to spot these animals since several groups tend to reside around the Park’s Headquarters.