Wild Again. David S. Jachowski
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suggested to researchers that ferrets were similar to other members of the weasel family in having a polygamous mating strategy. Ecological theory tells us that in polygamous societies, a male has to produce as many offspring as possible to maximize his genetic lineage. This requires that males keep exclusive access to as many females as possible. It is a matter of quantity, but also quality, because females typically select the best habitat in which to raise their litters. Thus, by association, males that protect prime habitat also are likely to have access to the most females and to females that are most likely to successfully rear their young.
Guarding of mates by male ferrets reached a fever pitch in the mating season from January through mid-March. Then, after a forty-five-day gestation period, kits were born in a natal burrow. Contrary to many other carnivores, such as wolverines and otters that remain in a single nest chamber for the whole litter-rearing period, female ferrets would move kits to new burrows at regular intervals. The mother would carry them with her teeth by the scruff of the neck, one at a time, when their eyes were still shut and they were not yet mobile.
Meeteetse researchers found that females did all the caring for the young, protecting them from birth in spring through to independence in late summer. A mother ferret at first nursed her kits, staying below ground for long periods of time. She killed prairie dogs only occasionally for her own food, until June, when she started moving the whole family to a burrow containing a freshly killed prairie dog. By late July and early August, kits were old enough to have motor control and come above ground for periods of time during the night. They would be cautious at first, with only the boldest of a litter of three or more doing more than sticking its head above ground, and never straying more than a few feet from the safety of the natal burrow entrance.
By mid-August, kits came above ground almost every night. On 93 percent of nights to be exact, typically between 1:00 and 4:00 A.M. The kits stood by their natal burrows as the mother hunted for food, until the silence was broken by one of the litter starting a tussle by charging at another, back arched, mouth agape, tail frizzed. Spotlighters found the kits to be curious, peering up from burrow entrances when the spotlighters approached. The kits noticed that any foreign object placed by their burrow deserved inspection. The small flags the researchers used to mark burrows often induced a spontaneous fit of play. Young kits would lunge off the ground, reaching the flapping flag at the top of the two-foot wire flags and landing in a puff of dust. They seemed amazed that they reached so high after a childhood spent mostly below ground or within two inches of the flat prairie surface. Collecting themselves after landing, as the dust cleared they sometimes chased their own tails, perhaps out of curiosity about their rapidly growing bodies.
By late August, kits grew to be as large as their mother or even larger, and more independent. They dispersed from their mother’s territory by the end of September and the prairie dancers had gone away. They were solitary for the next few months as behaviors shifted from rambunctious play to the pressures of adulthood and survival. By November, the former kits and older adult ferrets were active above ground only for, at most, one to two hours per night. With so little to observe, researchers switched their monitoring from spotlighting to occasional snow tracking when fresh layers of snow fell, searching for slight pawprints leading between burrows in skiffs of thin snow blown like sand into small waves by the bitter prairie winds. Biologists found that during the harsh winter months, when temperatures dropped below freezing and when white-tailed prairie dogs slept below ground for weeks on end in a state of torpor, ferrets similarly slowed their above ground activity. During peak winter periods, ferrets would spend up to six nights and days below ground without moving to another burrow. But the clearest pattern to the researchers was also the one attribute that has been known the longest about this species since its first discovery and description: that black-footed ferrets almost never leave prairie dog colonies; as the prairie dog goes, so goes the ferret.
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With the birth of conservation biology as a major scientific discipline, its participants formed a society in 1985 and soon thereafter launched an academic journal. The very first issue of the journal, Conservation Biology, published in 1987, opened with a four-page “progress report” by Tim Clark on the conservation of the black-footed ferret. He stated authoritatively on the first line that “black-footed ferrets are the most endangered mammal in North America.”
The remainder of the article painted a similarly grim picture. For what Soulé termed a “crisis discipline,” the black-footed ferret story of Meeteetse served as an ideal case study of conservation biology in practice. The series of events following rediscovery provided the classic example given in textbooks for the next several decades about how conservation biology requires skill sets from many walks of life to restore critically endangered species from the brink of extinction. And examples of ferret recovery efforts also demonstrated how failure to gain broad support and consensus on overall management direction can result in near-catastrophe.
In 1982, the year after rediscovery of ferrets at Meeteetse, researchers counted sixty-one individuals. That number increased in 1983 to eighty-eight and then again to 129 in 1984. The population was thought to be productive enough to exceed requirements of a minimum viable population. This meant that some ferrets could be captured and used as seed stock for captive breeding at the National Zoo, and once again at Patuxent. Yet because of political infighting between the State of Wyoming and a host of researchers and federal agencies, Wyoming decided that ferrets should not leave the state. Because no adequate facility existed in Wyoming to keep ferrets, let alone breed them in captivity, and because Wyoming insisted that any new breeding facility should be paid for by federal and private sources, capturing ferrets for captive breeding was put on hold.
Unfortunately, surveys by Meeteetse researchers found that by August 1985 there were only fifty-eight ferrets. Biologists feared the worst as the population continued to dwindle to thirty-one by September and to sixteen by October. There was great confusion over the cause of such a precipitous decline. Earlier that year plague was reported in the area, but studies of European polecats suggested that ferrets were likely immune to plague (an assumption that later turned out to be wrong; black-footed ferrets are actually highly susceptible to plague, as discussed in later chapters). Regardless, such a precipitous decline made the ongoing debates among state and federal biologists moot. The race was on to save the last few individuals in a last-ditch effort at captive breeding.
In October 1985, six of Meeteetse’s remaining ferrets were captured and transferred to a Wyoming wildlife research facility located in Sybille Canyon in the southern part of the state. Upon arrival, one ferret died of canine distemper virus. Then another died. Finally, because all six were housed in the same room at Sybille, the remaining four eventually contracted distemper and died.
A capture team was immediately sent to collect all remaining ferrets from the Pitchfork Ranch. Six more ferrets were brought to Sybille the following week. These animals did not die of distemper, but six individuals was hardly enough to start a captive breeding program. Certainly, such a number gave the captive breeders and ferrets only a small margin for error. But researchers knew that there was only a small chance that any more ferrets could have evaded capture and survived the canine distemper outbreak that was known to have spread through Meeteetse that year.
However, surveys in 1986 revealed that four individual ferrets survived in the core of the Pitchfork Ranch. There were two males and two females, which were monitored through the summer and found to produce litters of five kits each. Despite this glimmer of hope, by March of the following year it was decided that all known ferrets should be captured and moved to Sybille. In all, eighteen surviving ferrets were captured and taken into captivity. Some stragglers might have avoided this final capture effort, but they likely succumbed to disease or natural mortality in the coming winter or spring. A few might have lived as long as a year or two, but they would have been too few in number to persist and find each other to reproduce. All we know is that no more ferrets were seen in Meeteetse after March 1987.
With the last wild black-footed ferret at Meeteetse captured, something else was lost. Tim Clark paid the Hogg family the $250 reward he had promised for a confirmed ferret sighting, and there was still hope that rare ferret family groups remained hidden in remote pockets of the American West. During the thirty years since the Meeteetse rediscovery, the reward was increased to $5,000 and then