Captive Breeding to the Rescue
In their darkest days, only five Mexican gray wolves—including just one female—could be found in the wild. Professional biologists at the nation’s leading zoos and other wildlife facilities helped pull Mexican gray wolves back from the brink of extinction by creating a captive breeding program which now involves over 50 facilities across the United States and Mexico.
Launching the Program
The breeding program got off to a rough start. The only female—who was pregnant at the time of capture—gave birth to four males and one female, but the female pup died four days later. Fortunately, in 1981, at the Endangered Wolf Center (formerly Wild Canid Survival and Research Center) in Eureka, Missouri, this wild-caught female gave birth to one male and three female pups, all of which survived and reproduced in captivity.
By 1983 the captive breeding program was more firmly established with the birth of three litters totaling 15 pups. This breeding line of Mexican wolves is called the "McBride" lineage for the name of the trapper who caught the founders. Only one of the four males and the female successfully bred in captivity, and the unknown wild mate of the captured pregnant female is considered a third founder of the McBride lineage.
There were two other breeding lines of what were thought by some to be Mexican wolves, one in the U.S. called the "Ghost Ranch" line and one in Mexico called the "Aragón" line. Thanks to DNA testing, a team of experts was able to confirm that these wolves were in fact pure Mexican gray wolves, and these wolves were then included in the breeding program.
Today's wild wolves and all of those remaining in captivity can be traced to the seven Mexican gray wolves—four males and three females—that survived the U.S. government's extermination program.
Captive breeding has continued, and as of July 2008 there were 327 Mexican wolves living in 47 captive wolf breeding or holding facilities in the United States and Mexico, many of which are zoos.
You can find links to these facilities here.