DENVER — BACK to basics. A black-footed ferret ought to know how to behave as its ancestors always behaved - in the wild that is. Trouble is, since the black-footed ferret is nearly extinct, the United States Fish and Wildlife Service holds the last of them in captivity in order to increase their numbers. When a species has lived in captivity for too long it may not know how to hunt for its own food, or escape predators, or find natural housing for its young. One day, the feds hope to return black-footed ferrets to the wild. But how to prepare them for independent living? Basic training.
Enter Siberian polecats imported from the Moscow zoo. First cousin genetically to the black-footed ferret, the polecats are being used as surrogates for the rarer black-footed ferret in an experimental program in Wyoming and Colorado. While experts disagree about the definition of a species, many believe there are three species of ferret: the European (the domesticated variety), the Siberian, and the American black-footed. The last known wild American ferrets, all 18 of them, were rounded up in a prairie dog colony near Meeteese, Wyo., in 1987. There are now more than 200 in protective custody.
``We haven't come up with strategies for the release of the black-footed ferrets yet,'' says Dean Biggins of the Fish and Wildlife Service. ``But I'm going to recommend some kind of a halfway house based on the work we're doing here. It may not turn out to be what's best, but it seems logical.''
The US Army allowed Mr. Biggins and his colleagues to fill a 2,000-square-foot building at the old Army Depot in Pueblo, Colo., with dirt and prairie dogs as a seminatural environment for the Siberian polecats (who have lived in captivity only a few dozen years). Here they are learning to hunt their own dinners, raise their young on freshly killed meat, and camp underground in prairie dog burrows. If the polecats can do it, so might their black-footed relatives.
Biggins and company divided the polecats into four groups - two caged control groups and two for wilderness readiness - a feline version of ``Outward Bound.'' Those polecats in basic have been subjected to antipredator training. ``We used a dog to harass them - a stand-in for the coyotes,'' Biggins says. ``The dog picked them up and shook them, but didn't harm them. We did some experimenting with a motorized, road-killed badger, too. We called it `Robobadger.' But the thing moved too slowly and made a whirring noise and the animals weren't impressed.''
So far, the dog has made the best drill instructor. When a few polecats have been released from a control group and from basic, only those trained under the labrador retriever have survived.
The black-footed ferret's territory once stretched from Canada to the Mexican border with Texas. Their preferred cuisine is burrowing rodents, particularly prairie dogs. Agricultural and civil interests have searched and destroyed prairie dogs as vermin and plowed up their burrows, the ferrets' habitat. Without the burrows in which to hide, the ferrets' natural enemies - great horned owls, coyotes, badgers, hawks, and golden eagles - took their toll. Black-footed ferrets have lingered near the top of the endangered species list for years.
``The question of why they should be returned to the wild is an ethical one,'' Biggins says. ``If you make zoo animals out of the entire population of black-footed ferrets, they cease to be black-footed ferrets. Some of the animals will be retained in captivity in case reintroduction doesn't work. But reintroduction has always been our ultimate goal.''