San Andres National Wildlife Refuge not only contains the largest, intact area of Chihuahuan desert in the United States, it provides the largest landscape capable of supporting desert bighorn in New Mexico. Desert bighorn sheep require large areas of rugged mountainous terrain away from human disturbance. The refuge’s relatively undisturbed 57,200-acres are ideal for the bighorn, as well as many other species.
The refuge’s boundaries extend approximately 21 miles in length and six miles wide. While the terrain is comprised of steep, rugged mountains and deep canyons, the vegetation is mostly grasses and shrubs, like creosote and small cacti, yuccas and agave. The plant life changes with the elevation, from the basin floors at 4,200 feet up to 8,300 feet at San Andres Peak. Piñon pine and juniper cling to the higher slopes, while the springs and canyons support lush vegetation like desert willow and Apache plume.
To live in the Chihuahuan desert, animals must survive scorching summers, freezing winters and little rain. Within the San Andres range and Tularosa basin, wildlife have mastered desert living. Desert bighorn sheep
, for example, can lose 30 percent of their body weight when water is scarce and quickly recover. And their body temperatures can safely fluctuate several degrees.
The big ears of mule deer and black-tailed jackrabbits serve both for hearing and as devices for heating and cooling. Long-legged beetles and lizards are able to avoid touching the scorching earth. The steep mountains are ideal for mountain lions that depend on stealth to surprise mule deer. The rock caves also shelter at least 13 species of bats, important pollinators and insect hunters.
More than 150 species of birds inhabit the refuge for all or part of the year. In spring, riparian areas come alive with bird song. The colorful plumage of blue grosbeaks, summer tanagers, and yellow-breasted chats lend an almost tropical feel to these oases.