The mule deer, named for the large mule-like ears, occurs in the western mountains and plains of North America. In addition to the large ears, they are also easily distinguished from white-tailed deer by the smaller, black-tipped tail. Unlike white-tailed deer, mule deer have a leaping gait, termed stotting or pronking, in which all four feet contact the ground at the same time, producing a bouncing appearance as the animal travels at up to 45 miles per hour.
Mule deer bucks grow antlers during spring and summer; females do not grow antlers. The antlers of mule deer bucks branch into two main beams that have additional forks, whereas white-tailed deer have a single main curving shaft with tines extending vertically from it. The “velvet” skin covering of summer is rubbed off on the limbs and trunks of small trees (scrapes) in the fall, revealing smooth bone.
Bucks of 3-4 years of age compete for the right to mate with does in the “rut.” Rather than attacking each other with the intent to kill as they might do by piercing an opponent in the side with the antlers, bucks engage in a ritualized bout in which antlers are locked and a shoving match ensues. The opponent who tires first withdraws, and the victor is likely to mate with the most females. On occasion dueling bucks become trapped in an embrace of locked antlers, which can result in both animals perishing. Antlers are dropped off in winter and regrown the next year.
Mule deer prefer dry, rocky habitats with brushy diverse vegetation, where the younger plants offer more nutrition than mature vegetation. Mule deer are rather selective feeders, browsing on parts of herbaceous and woody plants, avoiding lower-quality grasses. They will also take berries in summer and acorns and nuts in the fall.
Fawns are born the summer after the fall mating season. The white-spotted fawn is well camouflaged, its coat resembling the dappled light filtering down through surrounding vegetation. It will attempt to remain stationary in the secluded location where the female gave birth for about 10 days, only bawling and running to escape if discovered by a predator. After gaining enough strength through nursing, the fawns will follow the doe and eventually lose their spots at about two months of age, when they are weaned. Young normally travel with the doe until about a year old. A natural lifespan will be about 10-12 years.
Mule deer population numbers have been declining in recent years. Several factors are responsible for the decline, including loss of habitat due to development and human populations moving into more remote mountain locations, the growing disturbance of oil and gas drilling in western public lands, and diseases. Chronic wasting disease is a fatal neurological disease caused by an abnormal protein that is picked up by an animal through the soil or tissues of a diseased individual. First observed in wild deer populations in 1981, by the year 2000 it was found in some 24 states, including New Mexico. Because the disease affects the nervous systems of deer, the New Mexico Game and Fish Department recommends that hunters avoid handling the brain or spinal tissues of harvested deer, and also avoid consuming brain, spinal chord, eyes, spleen, tonsils, or lymph nodes. There is no evidence that CWD is transmittable to humans.
James Taulman is a retired wildlife ecologist who enjoys exploring New Mexico’s natural areas and observing the state’s diverse wildlife. His research publications can be accessed at researchgate.net here; and wildlife videos are on YouTube, here.