Desert Bighorn Sheep Update

These rare specters are still surviving, perhaps even thriving, since their release in 2018 into the lowlands of the Sacramento Mountains near Alamogordo, New Mexico (90 miles north of El Paso). Forty desert bighorn sheep were released by the New Mexico Game and Fish to reintroduce this native species back into its original habitat. Since then, there have been several additional adults and juveniles seen in the Alamogordo herd, many without collars or markings, indicating recruitment or a growing population in the area. I recently spotted a population of about 12 individuals on US Highway 82 between mile markers 3 and 5 headed to Cloudcroft, NM. Competition and disease from other sheep species as well as over-hunting contributed to the accelerated loss of this unique indigenous species in the area.

The males have large curved horns that can be over three feet long, weigh over 30 pounds with a base circumference of a foot. These horns are used for defense both against predators and for mating-privileges with females. The females’ horns do not curve and are also used in defense and foraging. Their stocky bodies are covered with a tan to a light coffee-colored fur, accentuated with a distinct white rump. When observing the Alamogordo population, I noticed their coloration blended them into the landscape with remarkable precision, but that white hind patch made them easier to locate. My thanks goes out to one of our local game warden that alerted me to their rare presence at this location.

Their unique hooves’ construction provides the elasticity and buoyancy to scale the side of cliffs that seem to have no footholds at all, at least from a human perspective. They seem to defy gravity in their graceful ascents up sheer cliff faces without even a second thought of the possibility of falling. I can see how this adaptation has given them the advantage to avoid their natural predators such as mountain lions and coyotes. Having spent many years in the harsh heat of the desert during the summers conducting my own research on turtles, I can’t help but think that this ability to scale mountains may also help with their access to water, shade, cooler elevations and deft navigation of the harsh terrain. Other adaptations to their desert environment include being able to get some of their water from plants and enduring short stints of dehydration.

The U.S. populations had been declining and even were extirpated or locally extinct in areas from Texas to Utah until the 1960’s when conservation measures such as captive breeding programs and translocations helped bring the populations back into existence. In Texas reintroduction efforts were also made in the Sierra Diablo Mountains, Elephant Mountain Wildlife Management Area and Black Gap Wildlife Management Area. The numbers have been restored enough that limited hunting licenses are now offered. The money raised from these tags go back into conservation efforts specifically for the desert bighorn sheep.

Most individuals are released with GPS tracking collars, so wildlife biologists are able to determine their movements, herd behaviors and survival rates. Scientists also study population trends using visual counts using binoculars or aerial surveys by helicopter. Other types of data are collected from tracks, scat or droppings, and identifying areas where animals bed-down. Genetic information is collected from either capturing the animals and collecting blood samples or can be extracted from the scat, hair or carcasses. This article is dedicated to three Texas Parks and Wildlife Department employees who lost their life in a 2020 helicopter accident while contributing to these conservation efforts. I personally thank you, Dr. Bob, for sharing your expertise when the wildlife needed your help. You have left a lasting legacy.

Article by Dr. Jen Smith
Jsmith77@nmsu.edu