Endangered Mexican wolf pups fostered in Arizona packs this month, wildlife officials say

PHOENIX — Three Mexican wolf pups were fostered into a pack in Arizona in efforts to increase genetic diversity in the endangered wild populations, wildlife officials said.

Sixteen captive-born pups were placed with wild packs in Arizona and New Mexico over an eight-day period in early May, the Arizona Game and Fish Department announced on Friday.

The Mexican wolf was listed as endangered in 1976, and a captive breeding program led to the reintroduction of 11 wolves in Arizona in 1998.

The strategy of fostering pups by the Mexican Wolf Interagency Field Team (IFT) is in its eighth year, and there are 99 captive-born wolves who were fostered in the wild.

“Fostering is like a relay race for conservation,” Agapito Lopez, a wolf technician with the U.S. Fish and Wildlife Service, said in a press release.

“These pups start at SAFE (Saving Animals From Extinction) zoos and wolf centers, are handed off to be flown on donated private flights arranged by LightHawk, then given health checks and tube fed by our trained veterinarians, and finally are hiked into their new wild dens by our field staff. It’s a carefully orchestrated process involving dozens of dedicated individuals.”

The three wolves placed in Arizona dens this month came from the Brookfield Zoo in Chicago. Others were introduced from the Endangered Wolf Center in Missouri, Wolf Conservation Center in New York and Living Desert Zoo in New Mexico.

Pups are placed into dens within 14 days of being born and mixed in with similarly aged wild babies to be raised by the female.

The Mexican Wolf Interagency Field Team has not deducted significant differences in survival rate between fostered and wild-born pups at about 50%.

“Documenting the successes of pup fostering is a challenge that recovery partners are working to address, as recapturing fosters as grown pups or adults requires considerable resources and a bit of luck,” Assistant Director of Wildlife Management Clay Crowder at the Arizona Game and Fish Department said in the release.

“Pups are too young to be radio collared when fostered, but genetic samples are taken so they can be identified if captured later. The IFT is continuing to evaluate applications of existing and emerging wildlife tracking and monitoring technology to develop new ways of documenting survival of fostered pups.”

A new measure the IFT is using to monitor genetics is through DNA analyses of scat samples collected to document wolves that have not been collared.

Packs with collared adults will continue to be tracked through GPS and radio telemetry signals to check on pups who were placed in dens.

There were a minimum of 241 Mexican wolves recorded in the wild in 2022, up from 196 in 2021, the U.S. Fish and Wildlife Service announced.