As part of the protocol, Tom Thorne, a veterinarian employed by that Wyoming department, was made responsible for the welfare of the living BFFs and, as such, was given veto power over most field activities. He could halt any trapping procedures that he did not consider were in the animals' immediate best interests.
Thorne, who is stationed at the University of Wyoming in Laramie, is one of a handful of wildlife veterinarians in the nation and, among other things, a strong-minded man who is less enamored with hands-on research than are many laboratory zoologists. (For example, in 1983 Thorne called a halt to a plan by federal biologists to put radio collars on the Meeteetse ferrets. His reasoning was that the data collected might not be worth the risk of stress involved in capturing the endangered animals.) There was grumbling that Thorne was a zoological Luddite, but he stuck to his guns. As it turned out, that was good for the BFFs and probably for science in general.
In the spring of 1985, state and federal ferret authorities once again agreed that there were enough of the animals at Meeteetse to justify capturing a few that autumn to try breeding them in captivity. However, the plans of the BFF recovery team were shortly overwhelmed by nature. During the summer of 1985, sylvatic plague, a contagious rodent disease, broke out among the Meeteetse prairie dogs and began to kill them. Field observers suspected that entire families of prairie dogs (females and their litters) were "winking out"—a euphemism for dying.
Beyond killing off the prairie dogs on which BFFs prey, there was no evidence that this plague adversely affected them. But because of the publicity surrounding their precarious state, there was a great outcry that the disease might kill them and that the authorities must do something. In response, federal and state agencies used a hundred or so volunteer and temporary employees to dust thousands of prairie dog tunnels with a pesticide. The objective was to exterminate fleas that were known to spread sylvatic plague among prairie dogs. Despite the effort, the prairie dog and ferret populations continued to decline.
Still, the plans to revive a BFF captive breeding program went ahead. Six ferrets were captured in the fall of 1985 and placed under Thorne's supervision. All six of the BFFs died in the lab. The cause of death was found to be canine distemper, which is invariably fatal to BFFs and against which they do not seem to develop a natural immunity. At this point, it became apparent that distemper, not plague, had been causing the decline in the Meeteetse ferret population, and the well-intentioned pesticide work had been a distraction.
Most probably the Meeteetse ferrets naturally contracted distemper from other wild animals—badgers, skunks or coyotes—who are vulnerable to it and who also raid prairie dog colonies. However, there remains the suspicion that the virus—perhaps picked up from household pets—may have been brought in on the clothing of researchers, or "flea stompers," as Thorne came to call the pesticide applicators.
Thorne forthrightly blames himself for the loss of the six captured wild ferrets. "I should have immediately isolated all of them until we could find out what was happening. But I didn't and that was ignorant." (Thorne has a habit that is unusual among professional zoologists: He admits to mistakes, confesses he doesn't know this or that when he doesn't, and will say that while what he has done or plans to do seems reasonable, it may prove otherwise.)
Now armed with the knowledge of the specific disease that was threatening to wipe out the last remaining wild BFFs, the team captured six more Meeteetse ferrets in what then seemed a last-ditch effort to save the species from extinction.
In the summer and fall of 1986, Dean Biggins, a federal ferret researcher, and some of his colleagues were able to catch 11 more ferrets (four males and seven females) at Meeteetse, and with the six who survived the previous winter they were sent to a newly built, isolated research facility in Sybille Canyon, some 45 miles north of Laramie. This ferretry is particularly impressive, because when it was designed by Thorne and others, nobody knew much about what could and should be done for the animals. Most obviously the Sybille facility is a high-security one. Visitors are seldom permitted in, and those who are must take showers and put on sterilized clothing before entering the gymnasium-sized building that houses the BFFs.
The ferret cages are commodious. Each contains two den boxes that are ingeniously connected by tubing that simulates prairie dog tunnels. The den boxes are designed so that video cameras can be inserted without disturbing the animals. The animals can be constantly monitored on a bank of TV screens in an adjacent room.