Brookfield Zoo Helps Bring Mexican Wolves Back From Brink of Extinction

In 1976, when there were just seven left in the wild – none on the U.S. side of the border – the Mexican wolf was listed under the Endangered Species Act.

Since then, the U.S. Fish and Wildlife Service has worked tirelessly in conjunction with zoos around the country to bring this apex predator back from the brink of extinction.

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“Genetic diversity is probably the biggest scientific challenge that we have,” said Maggie Dwire, assistant coordinator for the USFWS Mexican Wolf Recovery Program. “The Mexican wolf dwindled to within seven animals of extinction and those, when they were first brought into captivity, were managed in three different lineages.”

In order to reduce the loss of genetic diversity, it was decided in 1995 to cross-breed those lineages.

“You can imagine that with only seven founding animals you already have an issue with genetics so to have that additional bottleneck is not good for the species,” Dwire said.

A captive breeding program was also established at a network of zoos around the country, including Brookfield Zoo, where wolves bred in captivity would be released into the wild to help bolster the genetic diversity of the species.

“Brookfield Zoo has been involved in partnering with U.S. Fish and Wildlife since 2003. When we renovated the wolf woods here at Brookfield Zoo we made sure it was large enough and could hold enough wolves that we would be able to be part of this recovery program,” said Joan Daniels Tantillo, curator of mammals at Brookfield Zoo. “We’ve been providing wolves for the wild for releases and also have been very involved in the cross-fostering efforts that have been happening recently.”

Two wild-born Mexican gray wolf puppies arrive at Brookfield Zoo as part of the U.S. Fish & Wildlife Service’s recovery program for the species. (Mexican Wolf Interagency Field Team / Chicago Zoological Society)Two wild-born Mexican gray wolf puppies arrive at Brookfield Zoo as part of the U.S. Fish & Wildlife Service’s recovery program for the species. (Mexican Wolf Interagency Field Team / Chicago Zoological Society)

Cross-fostering entails taking wild pups and placing them with a pack in captivity while at the same time placing puppies born in captivity with a wild litter.

“There’s only a very short period of time when you can successfully cross-foster puppies between mothers, and that is generally before their eyes open,” Tantillo said. “So within about 10 to 12 days of birth you have to very carefully orchestrate the transfer of one set of puppies to the other litter and back.”

While some have appreciated the efforts to bring back the wolf, not everyone is thrilled. Many ranchers view wolves as a threat to their cattle and livelihood.

“I think the biggest challenge is the conflicts with livestock,” Dwire said. “You have Mexican wolf habitat in an area that also has public grazing – so there’s going to be conflict there. With the Mexican wolf the challenge is compounded with the fact that at least in New Mexico a lot of the grazing is year round and so wolves have the potential to come into conflict (with ranchers) 100 percent of the year.”

One way the U.S. Fish and Wildlife Service helps manage that relationship is to compensate ranchers for loss of livestock to wolves and to use the permit process to try and keep grazing cattle and wolf packs apart.

“There are a lot of things we are doing to try to minimize conflicts with livestock and to build those relationships with the livestock producers,” said Dwire. “We’re now doing more on the front end to try and prevent wolves from depredating cattle in the first place. It used to be in an era when the population of the wolves wasn’t growing it used to be that we would respond to wolf-livestock conflicts by removing wolves and now we respond by working with the forest service to potentially alter grazing rotations so that permittees are using different allotments that are further away from wolf dens.”

It’s managing that relationship that Dwire is particularly interested in.

“The interesting thing about wolf recovery, at least to me, is that most species are endangered because of something that is really hard to fix – whether it’s invasive species or loss of habitat … wolves don’t really have any problems like that,” said Dwire. “The reason wolves are hard to recover is people. It’s a people issue and to me that makes it really interesting.”

Related stories:

How Artificial Insemination is Saving Mexican Wolf Populations

Brookfield Zoo Wolf Released into Wild Found Healthy in New Mexico

5 Endangered Gray Wolf Pups Born at Brookfield Zoo, 2 Sent to the Wild

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