The Coues deer, a subspecies of the white-tailed deer, inhabits the arid regions of the southwestern United States and northwestern Mexico. Notably smaller than other white-tailed deer, it sports a grayish coat and large ears. It is adept at navigating rugged terrains and exhibits crepuscular activity, being most active at dawn and dusk.

Odocoileus virginianus couesi, commonly known as Coues' white-tailed deer, is native to the southwestern United States and northern Mexico. In the U.S., it is primarily found in Arizona, New Mexico, and Texas. In Mexico, its range extends through the Sierra Madre Occidental and down into the states of Sonora, Chihuahua, and Durango.

Coues' white-tailed deer typically inhabit semiarid and arid regions, characterized by a varied climate with hot summers and mild winters. They are commonly found in areas with rugged terrain, including mountainous regions, foothills, and rolling hills. The vegetation in these areas often consists of scrubland, woodlands, and forests dominated by oak, mesquite, and juniper.

This subspecies of white-tailed deer has adapted to a niche that includes a diet primarily composed of browse such as leaves, twigs, and cacti, as well as grasses and forbs when available. The deer have developed behaviors and physical adaptations to cope with the scarcity of water and the harsh conditions of their environment, such as being more active during cooler parts of the day.