Wolf Cubs Born in Captivity Successfully Integrated Into Wild Packs

Good news from the wilderness: 20 Mexican gray wolf pups born in captivity were successfully integrated within wild wolf dens for cross-fostering.

The 20 wolf pups are the product of successful captive breeding programs in zoos and wolf centers in Missouri, New Mexico, Kansas, California, and Arizona. Since wolves need to connect to their population to ensure genetic sustainability, the cubs were placed in seven wild packs in Arizona and New Mexico.

This is called cross-fostering: placing 14-day old cubs in wild wolf dens that contain pups of similar age. Studies reveal that cross-fostered wolves have the highest rate of survival compared to any wolf-reintroduction methods.

According to Jim de Vos, an assistant director at the Arizona Department, cross-fostering has increased genetic diversity substantially. Managing genetic diversity has been one of the biggest challenges that Mexican wolf conservation is facing.

The Mexican wolf (Canis lupus baileyi) nearly became extinct as it was heavily hunted in the U.S. for the killing of livestock. After years of conservation efforts, 109 of these wolves have been reintroduced by 2015.

Cross-fostering of wolves started in 2014 with only two wolf pups. Over the years, 30 pups born in captivity were placed in foster dens. At least ten cross-forested wolves survived and have successfully integrated into wild wolf packs.  It is likely, however, that more cross-fostered wolves have survived and have gone unnoticed as the IFT does not collar and track each cross-fostered wolf.

But as of 2019, there are 163 wild Mexican wolves in Arizona, and New Mexico, an increase from 131 Mexican foxes, accounted for in 2018.

Wolves used to roam freely around North America until people settled in the West, farms, and ranches were established. Back then, settlers got rid of every wildlife that they can find: deer, elk, bison, turkeys, and everything. For animals at the top of the food chain, this means no available food for them, causing them to resort to eating the most available around them: livestock. Since then, wolves have been persecuted for consuming livestock. More 100,000 of gray wolves were killed in Montana alone from 1883 to 1942. The federal government even had extermination policies to eliminate wolves by hunting and poisoning them.

Since wolves which balance the elk population were eliminated, the elk were abundant. These elk caused the overgrazing of vegetation. Foxes and wolverines also suffered as they eat the food scraps of the wolves. Every five years or ten years, the elk would have a big winter die out. Coyotes also became widespread.

Gray wolves were protected under the Endangered Species Act in the 1960s. Except for Minnesota and Royale National Park in Michigan, gray wolves have been exterminated all over the U.S.  The federal protection improved the population of wolves. Wolves were reported in Idaho, Montana, Wyoming, Washinton, Oregon, and a few in California.

The Mexican Grey Wolves were also on their way to recovery but were still on an unstable population. From 1977 to 1980, there were only seven surviving Mexican Gray Wolves capture and bred in captivity.  Their cubs are reintroduced in Arizona and Mexico and the 20 cubs introduced in the wild are among those gains from this program.

The story of wolf recovery is not yet over: wolves need a connection to the population to ensure its genetic sustainability, and natural ecosystems for a healthy balance of species. As of today, wolves occupy only ten percent of their historic range yet continue to face persecution.