Black-footed Ferrets: Cloning May Be Last Hope

The work to save North Americas most endangered mammal has been and continues to be incredibly complex.

September 30, 20216 min read

Two ferrets scaled

By Mark Davis, Powell Tribune

In an attempt to supplement a struggling wild population of black-footed ferrets near Meeteetse, the Wyoming Game and Fish Department and U.S. Fish and Wildlife Service released 10 males and 10 females last week. Their goal is to maintain at least 35 individuals at the recovery site, but 20 may not have been enough.

While other sites have had better results, the endangered ferrets aren’t faring well on the historic Pitchfork and Lazy BV ranches adjacent to the Sunshine Reservoir complex. During population surveys in 2020, only one ferret was sighted by biologists. With about a week left in the current survey, only two have been reported.

“That doesn’t mean there isn’t more ferrets out there,” said Angela Bruce, deputy director of external operations for Game and Fish, but “we definitely have concerns with the Meeteetse reintroduction area and will continue to focus efforts there on the disease management.”

The work to save North America’s most endangered mammal has been and continues to be incredibly complex. Starting with just 19 individuals taken from the Meeteetse about four decades ago, more than 10,000 have now been bred in captivity and those that pass intense testing (capable of making kills to feed themselves) are released at several sites across the West.

As few as 200 to 300 ferrets now live in the wild; 3,000 are necessary to consider the species — often referred to as BFFs — fully recovered. They’ve been reintroduced at 29 sites across eight states, plus in Canada, and Mexico, according to Fish and Wildlife .

While the program has had great success, worthy of celebrating, black-footed ferrets only live for a short time, according to Robyn Bortner, captive breeding manager for the National Black-Footed Ferret Conservation Center. “In the wild, some of the original populations, especially in Meeteetse, were estimated to have only mean life expectancy of 0.9 years.”

Ferrets unable to raise a litter in their first year of life are often lost in the effort to repopulate the area, Bortner said. Predation and disease seem to be the culprits.

All release sites and native prairie dog populations in the area are treated for disease, as silvatic plague and canine distemper are both deadly to the ferrets and widespread. In Meeteetse, thousands of acres were dusted for the fleas that carry plague and prairie dogs — the ferrets’ main food source — were inoculated through bait before the endangered predators could be released.

Yet, despite intense efforts by scientists studying the species for more than 40 years, there are inherent issues that have stymied scientists. The most difficult challenge to overcome is the lack of genetic diversity, due to the small number of ferrets originally used in the captive breeding program. It is a tough nut to crack.

Bortner said problems associated with the ferrets’ lack of genetic diversity have been popping up.

“Due to their inbreeding they do have a slightly suppressed immune system,” Bortner said. “They are very susceptible to [gastrointestinal] problems and can die within 48 hours if left untreated.”

Then came Elizabeth Ann.

Elizabeth Ann was cloned from preserved DNA from Willa, a wild black-footed ferret that died almost 40 years ago. The clone was brought to term by a domestic ferret and then transferred immediately to the captive breeding center near Ft. Collins, Colorado. The process, from concept to a living clone, was extremely quick.

“It actually happened much quicker and easier than we had expected,” said Shawn Walker, chief science officer for ViaGen, which does genetic preservation and cloning research.

Elizabeth Ann was the first of what they hope are many clones that carry tens of thousands of unique alleles (one of two or more alternative forms of a gene that arise by mutation and are found at the same place on a chromosome) that can possibly give the captive breeding program a fighting chance to breed healthier, more genetically diverse ferrets.

With permission from federal officials, the California conservation organization Revive and Restore has now taken DNA samples from another specimen in efforts to clone a male. 

However, the donor died from canine distemper virus and its DNA contains particles of the deadly disease. Scientists for the organization now need to strip the virus from the cells before they can clone the possible mate. Fortunately, ferrets in the captive breeding center can live up to eight years, so they may have time to breed Elizabeth Ann.

Further down the road and much more difficult to achieve, Revive and Restore hopes to develop disease-resistant clones.

Representatives from several organizations involved in the process met for a virtual conference last week, led by Dr. Lenox Baker, a retired heart surgeon who owns the Pitchfork Ranch outside Meeteetse. He has continued running the historic cattle operation and supports reintroduction efforts on his land. It’s a seemingly odd mix.

One of the reasons for the extirpation of black-footed ferrets from most of their traditional range was due to massive extermination efforts by ranchers to rid their land of prairie dogs, Baker said. But he insists reintroduction efforts of ferrets have made no difference to his ranching efforts.

“Nor do the prairie dogs,” he said. “To those ranchers out there, listen to this: I would not be at all hesitant to have this kind of project on your ranches.”

Ryan Phelan, of Revive and Restore alluded to the myths still being prevalent.

“I wish more people understood that dynamic and how healthy it can be for a ranch owner with cattle,” Phelan said.

Partnerships with landowners in Wyoming have been key to the species recovery efforts, according to Zack Walker, Game and Fish non-game supervisor.

“We have phenomenal partnerships with the Lazy BV and Pitchfork ranches who are dedicated to black-footed ferrets and their success,” Walker said. “Much of what we’ve been able to accomplish for ferrets is due to their considerable support, of which we’re grateful and appreciative.”

Ashlee Lundvall, a Game and Fish Commissioner from Powell, was on hand for the release of the 20 additional ferrets last week. It continued an effort to restore the ferrets in the Meeteetse area that began in 2016.

Lundvall called it an honor to participate.

“I was so thankful that my daughter, Addison, was able to join me and experience the thrill of seeing these amazing creatures headed back to their natural habitat,” she said in a statement. “This is a side of conservation that I want her, and those of her generation, to see and be part of.”

The department plans to release 10 ferrets in Shirley Basin near Laramie in the coming weeks — the first place in Wyoming to reintroduce black-footed ferrets following successful captive breeding.

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