The matriarch of the Leopold Pack—known to Mexican wolf biologists as Alpha Female 1346—began life as an experiment. Days after she was born in May 2014, biologists snuck the cinnamon-hued pup and her brother into the den of a wild wolf pack in New Mexico’s Gila National Forest, nestled them among the family’s own trio of tawny newborns, then tiptoed away.
At the time, bolstering the Mexican wolf population with cross-fostered pups—offspring that are typically born in captivity then placed into wild dens—was a risky gamble. Biologists had little idea whether the mother wolf would accept the newcomers. But, to their relief, it worked: The mother wolf adopted the foster pups as her own. And the novel experiment was a turning point in the decades-long effort to restore Mexican wolves—the world’s rarest type of gray wolf—to their native territory in the American Southwest.