The black-footed ferret was believed to be extinct when a small group was discovered on a Wyoming ranch 28 years ago.RICK WILKING
Twenty-eight years ago, a Wyoming rancher's dog carried a strange-looking dead animal home to its master.
The cream-coloured creature was about the size of a house cat, with a slim body and black feet, face and tail tip. Puzzled, the rancher took it to wildlife biologists, who were stunned to discover an animal thought extinct: a black-footed ferret.
Further examination revealed that the rancher's property was home to a small, stable population of these ferrets. But six years later, disease cut their numbers to just 18 and panicked biologists raced to round up the remaining animals, rightly suspecting that they would never find others.
Now, the process is being reversed: This fall, the black-footed ferret will return to Saskatchewan, where it hasn't been seen since the 1930s, when settlers converted prairie to farms, decimating the ferret's prairie dog prey.
While the ferrets have already been reintroduced to Wyoming and other places in the United States and Mexico, this will mark a first in Canada. Most of the 40 animals to be released in Grasslands National Park will come from the Toronto Zoo, which runs one of six captive breeding programs set up across North America two decades ago.
But before being given their freedom, the animals must receive something crucial to their success in the wild: survival training.
The black-footed ferrets have to go to boot camp.
"It's pretty essential for pre-conditioning," says Maria Franke, the Toronto Zoo's curator of mammals.
The problem of how to "re-wild" animals bred in captivity is cause for much hand-wringing these days as habitat destruction forces more creatures onto endangered-species lists. Animals raised with regular meals and nary a predator in sight simply can't be let loose to fend for themselves. They need to learn how to hunt for their own food and find shelter. The hardest part for most is recognizing and escaping those animals that want to make a meal out of them.
The Toronto Zoo's young ferrets will be flown next month to the U.S. Geological Survey's facility in Fort Collins, Colo., where they will live with their mothers for six to eight weeks in large, closed outdoor pens.
Boot camp is crucial, as biologists learned after their first disastrous attempt at reintroduction in Wyoming in 1991. The black-footed ferret was taken straight from captivity into the wild and nearly every ferret died in the first year, mostly in the jaws of coyotes and badgers.
But a series of trial-and-error experiments led by wildlife biologist Dean Biggins of the U.S. Geological Survey has since produced today's regimen for toughening up the creatures. Unwilling to risk the few remaining ferrets, Mr. Biggins brought Siberian polecats from China - the ferrets' closest living relatives - to act as stand-ins for testing boot-camp techniques.
He raised the polecats in the same one-by-1.2-metre cages in which the ferrets were first reared, testing their reactions to mock predators, including the rather disappointing robo-badger.
"He was a road-kill badger mounted on a toy truck chassis and we'd chase them around with it. But robo-badger was slow and although he looked like a badger, he just didn't behave like one," Mr. Biggins admits.
So a more convincing stuffed owl was rigged to swoop down when the polecats passed through an infrared trip line.
The first generation fled to their boxes, where they cowered for hours. But each successive generation became less wary and by the fourth generation very little spooked them.
While the results were no surprise, Mr. Biggins hoped that his next experiment would show that the unwary behaviour was reversible and not genetically hardwired. He wanted his next experiment to show that by taking that fourth generation and raising them in large pens that simulated their natural environment, their offspring would eventually relearn how to be wary and avoid predators.
He created as normal a habitat as possible while still offering protection from predators so that the animals could live long enough to unlearn bad habits. To his relief, each successive generation became increasingly wary, until their reactions were close to normal.
"Why that happened, we don't know," Mr. Biggins says. "Was it simply lack of human attention? Or being in burrows where mom can transmit escape behaviour? Or are they more physically fit?"
While he is painfully aware that not every animal is ready for release, Mr. Biggins says it's too expensive to assess each individual. The black-footed ferrets are simply given the best possible preconditioning, and the rest is up to them.
Still, animals released today have survival rates 10 times better than those raised in cages and there are now about 800 black-footed ferrets living in the wilds of the U.S. and Mexico.
Biologists have had less success with the masked bobwhite, a plump short-tailed quail native to Mexico and Arizona. After cattle-grazing decimated their grassland habitat, they were believed extinct until pockets of them were discovered about 40 years ago.
While the birds bred well in captivity, they had no survival skills. At Arizona's Buenos Aires National Wildlife Refuge, sterilized Texas bobwhites males were brought in to act as foster parents, teaching the chicks how to be wild.
The system worked until the males were released along with their foster chicks, says veterinarian Glenn Olsen of the U.S. Geological Survey.
"Texas bobwhites are bigger, stronger birds and they tried to mate with the female masked bobwhites - they out-competed the male masked bobwhites," he says.
The females laid infertile eggs and the population stagnated.
So while the masked bobwhites succeeded in boot camp, the populations of masked bobwhites did not increase, which was the point of reintroduction. For the past two years, researchers have put the program on hold while they go back to the drawing board, Dr. Olsen says.
The opposite seemed to occur in Rio de Janeiro, where conservationists worked to reintroduce the golden lion tamarin, only to encounter another unexpected obstacle.
Originally victims of the fragmentation of coastal forests, these small red and orange primates later became victims of captive-rearing techniques.
"They were like human beings thrown into the forest and told to get on with it," recalls primatologist Anthony Rylands, deputy chair of the International Union for Conservation of Nature's species survival commission.
The golden lion tamarins had trouble swinging on branches because fixed poles used in captivity don't bob about the way real branches do. Regularly replenished food bowls meant that they had no idea how to forage. And they had never dodged a hungry forest cat.
So branches were made more realistic and their food was hidden, encouraging them to at least get up and look for it. Biologists even captured wild golden lion tamarins and put them in with the captives, hoping that they would learn a thing or two.
But the captives were so unfit that all the boot-camp training didn't help: They just couldn't keep up with their wild cousins.
"The captive animals remain pretty damned useless [in the wild]" Mr. Rylands says.
So much for boot camp. But in the case of golden lion tamarins, the reintroduction turned out to be somewhat successful anyway.
"What is important is they breed and the little babies get going," he says.
Offspring, growing up with real tree branches and limited provisioned food, break off into peer groups at about 13 months and teach each other the ways of the wild.
Of the 1,000 wild golden lion tamarins in Brazil today, roughly one-third are estimated to be descendants of captive-bred animals.
The problem now is there is nowhere for these endangered animals to go.
"Every bit of forest has now got golden lion tamarins in it," Mr. Rylands says. "A lot of the battle now is to connect fragmented habitat together."
The International Union for Conservation of Nature warns that extreme fragmentation of the habitat of golden lion tamarins means that they are not likely to reach even 2,000 individuals, the minimum estimate for a self-sustaining population.
Which means that despite all the work, golden lion tamarins may never come off the endangered-species list.
Sharon Oosthoek is a Toronto-based writer who specializes in science and the environment.