Cross-fostering is a strange and delicate thing to attempt. Biologists take newborn pups bred in captivity and slip them into a wild den among a wild litter of the same age, close enough in size and scent that the wild mother raises them as her own [1].
The Mexican wolf recovery plan set a target: 22 of those fostered pups surviving two years in the wild by 2030. As of this month the count is 23 [1]. The goal was met four years early.
The work is shared between the Arizona Game and Fish Department, the US Fish and Wildlife Service and the New Mexico Department of Wildlife [1]. In early June they placed five more newborns into wild dens [1].
The wider population is still small - the 2025 mid-winter count found 317 Mexican wolves in the United States [1]. What the milestone measures is not abundance but method: the technique of handing a captive-born pup to a wild mother works well enough that the recovery plan's own bar has been cleared ahead of schedule.
