Arizona wildlife officials say they’ve introduced 16 captive-born endangered Mexican gray wolf pups to wild dens.
The process known as cross-fostering is meant to increase genetic diversity in the wolf population.
The newborn pups were placed within 14 days of being born and bred at four facilities across the U.S.
They were put in five wild dens in New Mexico and one in Arizona with similarly aged wild pups.
Biologists hope the breeding females will care for the captive-born pups alongside her own.
The Arizona Game and Fish Department says the cross-fostered pups have a 50% survival rate within their first year, the same as wild pups.
It’s the eighth year for the cross-fostering program that has placed nearly 100 pups in wild dens.
Though numbers of Mexican wolves in the wild are at their highest ever level, a lack of genetic diversity continues to hamper the program.