Ferret bootcamp: History

The black-footed ferret, or Mustela nigripes, has led a dangerous life, even for a member of the weasel family.

Historically, ferrets lived in central North America, from the Canadian-U.S. border in Alberta and Saskatchewan, all the way to the northern tip of Mexico. However, that is no longer the case.

The black-footed ferret originally thrived all across the central United States, Mexico and Canada. The numbers on the map represent possible ferret re-introduction sites.
Adapted from a photo courtesy of Travis Livieri, USFWS

According to Travis Livieri of the United States Fish and Wildlife Service (USFWS), the ferrets lived in grassland plains, but when settlers arrived, so did a large problem.

"The settlers transformed grasslands into fields for agriculture," says Livieri. "But as human populations exploded and needed more space for urbanization, the ferret's habitat was one of the first to go."

But even then, the ferrets persevered.

That is, until their main source of food, the prairie dog, was viewed as a menace to fields and crops, and therefore had to be eliminated through poisoning.

Along with that came increases in cases of canine distemper and a variant of the bubonic plague known as sylvatic plague, both of which are lethal to ferrets. Livieri says that it was like the angel of death in the numbers of prairie dogs that died or were killed.

"I can remember seeing an old photograph with a large pile of dead prairie dogs from just one day's worth of hunting in Arizona. They were all hunted or killed by disease - If only they knew what they were doing to the magnificent black-footed ferret."

To no one's surprise, those factors contributed to the ferret being listed as extinct in the wild in the 1970's. It was gone forever.

And then, hope.

The Toronto Zoo, which has a ferret breeding program in participation with the Fish and Wildlife Service, has been directly involved with bringing the ferret back from the edge of extinction. The curator of mammals at the zoo, Maria Franke, says that a hunter in Wyoming in 1981 saw his dog return with a dead ferret in its jowls.

"The U.S. government immediately located the 130 member black-footed ferret colony, and after they were ravaged by plague in the mid 80's, the government stepped in and captured the remaining 18 individuals to begin a captive breeding program," says Franke.

Massive numbers of prairie dogs were killed when settlers first came to North America, as they were viewed as agricultural pests.
Courtesy of Travis Livieri, USFWS

"Every ferret on the planet today is related to those 18 individuals."

The first re-introduction program for ferrets began in 1991 in Wyoming, and has since expanded to areas in eight states, as well as one in Mexico and in Canada. The Canadian site, Grasslands National Park in Saskatchewan, began introducing ferrets in the fall of 2009.

The re-introduction process begins with pups being reared with their parents in a breeding facility, like in the Toronto Zoo, before they are transported to a pre-conditioning centre. The main area for this is the USFWS National Black-footed Ferret Conservation Center in Colorado, where the ferrets are trained to survive in the wild.

According to Livieri, who works at the re-introduction site in South Dakota known as Canata Basin, the kits (young ferrets) are introduced into their new home at approximately 120 days, the normal time for young adults to leave their mother in a wild population.

They are vaccinated against plague and canine distemper before they are released, to give them some protection against the deadly diseases. But after that, it is up to the ferrets.

"We give them a chance," says Livieri. "And now all we can do is monitor their habitat, track them, and hope that we did enough."