Rio Grande Zoo, Albuquerque, New Mexico; Oct 25, 2007.

From Wikipedia:
The Mexican Gray Wolf is the rarest, most genetically distinct subspecies of the Gray Wolf in North America.
Until recent times, the Mexican Gray Wolf ranged the Sonora and Chihuahua Deserts from central Mexico to western Texas, southern New Mexico, and central Arizona. By the turn of the 20th century, reduction of natural prey like deer and elk caused many wolves to begin attacking domestic livestock, which led to intensive efforts by government agencies and individuals to eradicate the Mexican Wolf. Hunters also hunted down the wolf because it killed deer. Trappers and private trappers have also helped in the eradication of the Mexican Wolf. (Note that recent studies completed by genetics experts show evidence of Mexican wolves ranging as far north as Colorado).
These efforts were very successful, and by the 1950s, the Mexican Gray Wolf had been eliminated from the wild. In 1976, the Mexican Gray Wolf was declared an endangered subspecies and has remained so ever since. Today, an estimated 200 Mexican Wolves survive in the wild.