Eleven Mexican Gray Wolf Pups Released Into the Wild

The pups were part of a cross-fostering program to boost genetic diversity in the endangered subspecies

A gloved hand holds a small wolf pup
A Mexican wolf pup less than 14 days old is given a health check before being placed into a wild den in New Mexico. Mexican Wolf Interagency Field Team

To help bring back the Mexican gray wolf, officials placed 11 captive-born Mexican gray wolf pups into the dens of wild packs this spring to boost the genetic diversity of the endangered subspecies. The release was part of a cross-fostering program led by multiple agencies including the U.S. Fish and Wildlife Service.

“Since the inception of the program, 83 pups have been placed into wild wolf dens and as a result, [the majority of] genetic metrics have shown improvements, which bodes well for the long-term survival of the Mexican wolf,” Jim deVos, the Mexican wolf coordinator at the Arizona Game and Fish Department, says in a USFWS statement. “Planning has already begun for the 2023 fostering program, with a goal of getting more pups in dens next year than this year.”

Mexican gray wolves, a subspecies of the gray wolf, were once common across parts of the Southwest and Mexico but were nearly wiped out after the US government paid hunters to trap and poison them in the 19th and early to mid-20th century. 

With only a few individuals left in the wild, the subspecies was listed as endangered in 1976. Wild wolves were captured and bred in zoos. In 1998, the first 11 captive wolves were reintroduced into Arizona and New Mexico. Mexican gray wolf numbers grew from 22 total wild and captive wolves in 1976 to 309 in 2004. 

The cross-fostering program, now in its seventh year, mixed the 11 captive-born pups with similarly-aged wild pups, per the statement. The mother will feed and care for all young, and they’ll learn the skills needed to survive in the wild. According to the USFWS, the captive-born pups will have the same survival rate as wild-born pups in their first year—about 50 percent.

“Although the 11 pups fostered is lower than hoped for, it is a major contribution to managing genetic improvements in the wild population,” deVos says in the statement. Last year, a record 22 captive-born pups were released into seven wild dens. 

An enormous problem in trying to increase the populations of critically endangered species is increasing their genetic diversity. When a population dwindles to near extinction, like in the case of the vaquita porpoise native to coastal Mexico, this leaves little variety in their genetic backgrounds. This can leave a near-extinct species vulnerable to mutation and unable to adapt well to the environment. The Fish and Wildlife Service claims that the pups were bred specifically with re-introducing genetic diversity in mind.

The Mexican wolf recovery program has received criticism from conservation and environmental groups, who say more could be done to help the wolves, like allowing the population to grow bigger and giving wild individuals more space to roam and breed. The criticism has been fierce enough to even elicit lawsuits claiming that government workers were ignoring science and putting the wolf on the road to extinction. Ranchers and politicians also criticize the program, saying the wolves kill livestock and the population is already too high. 

But officials call this year’s release a success. 

“We all coordinated together to work towards a common goal, just like it has been in previous years," John Oakleaf, the Mexican wolf field projects coordinator for USFWS, tells Arizona Republic’s Lindsey Botts. "I think we do a tremendous job. One thing that was different this year from previous years was that all the cross fosters took place in a 15-day window. So it was a really tight window of work.”

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