There was concern about the purity of the captives. Says Carley, “We caught four hundred canines down there from late 1974 to mid-1980. The majority of those were coyotes or obvious hybrids.” He looked also at animals already in zoo collections which curators touted as additional candidates for the captive-breeding effort. Many of these animals, Carley saw, were hybrids. To protect the breeding stock, Carley eliminated all but forty-three of the purported red wolves. As he and his staff continued to breed the forty-three and look at the offspring of each pairing, they decided that most of them were coyote crosses, too. They eliminated all but seventeen individuals, which were deemed to be pure red wolves. Three of these never bred, so today the entire captive-breeding population of red wolves descends from fourteen individuals.
For years, all the known red wolves in the world were in captivity. And most of them were at the Point Defiance Zoo’s Graham, Washington, red-wolf breeding facility, far from the zoo in Tacoma. The facility is on the grounds of a mink farm owned by Dale Peterson, a member of the Point Defiance Zoological Society’s mammal committee, which has been interested in the plight of red wolves since the 1960s. Peterson’s mink farm consists of several acres of sheds with rows of small elevated pens for mink, surrounded by a dense forest of fir and spruce. The breeding facility, behind a high chainlink fence and locked gates, consists of eighteen pens, some a hundred feet square, others fifty by a hundred feet, arranged in a five-acre rectangle. These pens have fir, spruce, oak, and alder trees in them, and most have a dense growth of grass and shrubs which provide cover for the animals. Here and there, the wolves have dug holes, and from time to time they unearth strange objects. Says Sue Behrns, caretaker of the facility, “Years ago, Purina owned the mink ranch. Somebody would take stuff out and dump it in the woods. When they put the pens in, some of it got buried. Sometimes, the wolves dig up old equipment, a wrench, part of a machine.”
Such encounters are only part of the oddness of the scene. It’s a little strange to think of this almost tropical wolf breeding in the somber, rainy gray of the Northwest. But, Behrns explains, the natural history of mammals these days often takes unnatural turns. Whether the turns have altered the wolves to the point where they can no longer be considered wild is the key question.
Behrns has bright-blue eyes, sun-reddened cheeks, and an easy, melodic laugh. As she drives up to the cyclone fence that surrounds the facility, the wolves howl spontaneously. But as soon as the visitors get out of their vehicles, the wolves dash to the backs of their pens or go into their dens, which are concrete septic tanks left standing above ground. They trot nervously along the back fences, and squat to urinate timidly. Some lower their bodies and walk in a sort of slow crouch, their heads and necks low, their ears flattened out. It’s hard to say whether that is the nature of the animal or part of the conditioning of the program. From the start, the managers wanted to keep them shy of humans. Says Carley, “Every contact that a wolf has with a human should be a bad experience. You draw blood, give ’em shots, get in, get out. It’s for the benefit of the wolf. They shouldn’t ever want to get near a human being.”
The aim of this breeding program is to share the genes of all fourteen founders as widely as possible by means of judicious pairings. The recovery-plan goal is to have 320 wolves in captivity. Currently there are about half that number, and they are now spread among two dozen facilities in various parts of the United States. The breeding is intensive and very selective. Every year, the captive-breeding team meets to decide which wolves should be tried for breeding, and every year young wolves are shipped from Graham to other breeding centers, or to Alligator River for release.
Most of these animals, Behrns says, are tame: some of the old wild-caught animals will chase the food truck along the fences or come to within a few feet of the fence and follow Behrns as she passes. When strangers come in, however, they get very shy. “If it’s just one person, they may not be quite as shy,” says Behrns. “If it’s two, it may mean that somebody’s going to get caught.” They have all had the experience of having humans come in, put a noose over their necks or catch them in a big salmon net, and hold them down while blood is withdrawn.
With the emphasis on breeding, there is a fair amount of intervention into the lives of these creatures. A critical responsibility of Behrns’ is figuring out exactly when a female is ready to breed. “We go in every other day to check them. As soon as we know they’re close, we go in every day. We check for vulva swelling, and take smears and a blood test.” The smear is examined under a microscope. When a female wolf comes into heat, the epithelial cells square off and their nuclei get very small. Blood samples are checked for the lowered estrogen and increased progesterone levels that indicate a wolf is ready for insemination. The tests are done at Puget Sound Hospital’s gynecological clinic by a technician who does exactly the same tests on human blood samples. Behrns looks forward to the day when it will be possible to test hormonal levels with fecal or urine samples, because it will be less stressful to the wolves.
For all the handling, the wolves seem natural and alert. “At whelping season,” says Behrns, “as soon as you drive in you know somebody’s given birth.” They all get excited, and walk around more warily. “They get very protective of the young. A female gave birth in a depression, fifteen feet from the fence. As soon as I walked in, the male was barking at me, even though he was in a different pen.” She adds, “They all like puppies, which is something that works to our advantage. We can put a puppy a few days old into another pen if we need a foster mother,” and the puppy will be accepted.
Parental devotion was not in itself proof that the red-wolf reintroduction would work. At the outset, reintroduction was still more a hope than a proven management technique. It had been done with peregrine falcons, black-footed ferrets, and a handful of fish species, but never had a large predator extinct in the wild been reintroduced. Moreover, because red wolves had vanished from the wild before any comprehensive study had been done of them, managers knew little about how they would act in the wild. When the project began, recalls Carley, “We thought we knew how it could be carried off. But we needed a laboratory to demonstrate that some of our theories were correct. The main thing was that we could control the wolf if it got loose—that we could recapture it.” They decided Bulls Island, a five-thousand-acre island in Cape Romaine National Wildlife Refuge, South Carolina, was the laboratory they were looking for.
In 1976, a pair of red wolves was released on the island. Bulls Island is three miles from the mainland, but those three miles are marsh, rather than open water. At low tide, wolves can walk and swim across. Says Carley, “In our first attempt, our female got to the mainland in eleven days. When that happened, we thought it was the end of the world. We’d made all kinds of promises to kill the animal if it got to the mainland, so it was time to put up or shut up. The assistant manager and I chased after her for over forty hours.” They finally recaptured the female by shooting her with a tranquilizing dart from a pursuing helicopter. The male also left the island and had to be recaptured. The project was a public-relations disaster.
“This called for a serious regrouping,” Carley continues. “Over the next several months, we determined that a dog from an adjacent island had chased the wolf and caused her to flee. We also concluded that they had not been acclimated long enough.
“We had to fight with the administration, all the way to Washington, to get authorization for a second attempt. Because of our openness during the first introduction, we had a lot of following in the press. Due to our openness with the public, they became understanding and supportive and wanted us to try it again.”
In 1977, another pair of red wolves was brought from Washington, and put into a pen on Bulls Island. They were soft-released—that is, they were kept penned for six months to acclimatize, and released early in 1978. For eight months, they stayed on the island without any problems. “But the agreement was that this was a short-term experimental introduction
,” says Carley. The wolves were recaptured and returned to captivity. “We would then start looking for a long-term release site.”
The Fish and Wildlife Service looked for a release site that would support more than a pair of wolves. As Carley explains, “To get genetic viability and gene flow, you needed to have a population on the mainland.” In 1979, they proposed to release red wolves on Tennessee Valley Authority properties at Land Between the Lakes in Kentucky. The proposal required detailed public-hearing and rulemaking procedures, and the reintroduction proposal was not published in the Federal Register until 1983. In 1984, the Tennessee Wildlife Resources Agency, responding to hunters who feared that release of wolves would curtail their hunting in the area, rejected the proposed introduction. It looked as if the wolves had no place to go.
But in the same year, the Prudential Insurance Company donated 118,000 acres of freshwater swamp, pocosin, and brackish marsh habitat in northeastern North Carolina to the Fish and Wildlife Service. A subsidiary of Prudential had planned on mining peat from that land to manufacture methane, but commercial fishermen protested, fearing the effects of peat mining on water quality and nearby fisheries. The National Wildlife Federation, concerned about the loss of increasingly rare pocosin wetlands, sued to overturn the Corps of Engineers’ issuance of a permit to drain these wetlands. Faced with growing opposition, Prudential gave up on the project and, with help from the Nature Conservancy, conveyed the land to the Fish and Wildlife Service for protection as a refuge. At the time, wolf reintroduction was not a primary aim of the transfer, but the site seemed perfect for wolves. It was surrounded by water on three sides. In the middle was a navy bombing-practice range, which kept nearly all human activity away. The neighboring farmers raised soybeans and tobacco, not livestock. Moreover, since wolves had been gone from this region for nearly two hundred years, there wasn’t a local tradition of wolf hunting.
Warren Parker, who succeeded Carley as coordinator of the red-wolf reintroduction, saw that the only traditional use that had to be accommodated was hunting. He concluded that, with careful attention to the attitudes of hunters, hunting and wolf reintroduction could get along just fine.
The reintroduction could be tailored to the circumstance. Under the terms of the 1982 amendment to the Endangered Species Act, the Secretary of the Interior may designate an introduced population of a listed species as “experimental-nonessential” if loss of some of the population will not jeopardize the survival of the species. “Experimental-nonessential” regulations might, for example, allow ranchers to shoot wolves if they saw the animals attacking their sheep or goats. When the Fish and Wildlife Service designated the Alligator River Refuge wolves an “experimental-nonessential” population, it required farmers who saw wolves taking their livestock to contact Fish and Wildlife Service officers or state conservation agents rather than shoot the wolves. But if hunters or trappers unintentionally took a wolf and immediately reported it to the refuge manager, they would not be prosecuted. The regulation declared, too, that wolves could be taken in defense of human life. Nor would citizens who shooed wolves away from their houses and roads—an act usually regarded as hazing under the Endangered Species Act—be prosecuted. Fish and Wildlife Service officials hoped the less stringent protections would generate public support for a program that might otherwise have faced stiff opposition.
In November 1986, four pairs of red wolves were shipped from Graham, Washington, to the refuge. And in 1987, the first of the wolves were released. Two litters were born in the wild in April 1988, two more in 1990. Each year, the program released at least two pairs with litters of young too small to travel. Candidates for release arrived from Graham and were held in a camp on Sandy Ridge, a strip of higher ground that runs through the center of the refuge and provides a cool, pine-shaded setting for eleven fifty-by-fifty-foot holding pens. They bore litters there and acclimatized. By releasing adult wolves with sixteen-to-seventeen-week-old pups, the managers hoped to tie them to the release sites. It seemed to work. The number of wolves increased.
Things seemed to be going well. But in January 1989, at a meeting in Atlanta of the red-wolf recovery team, David Mech raised the old question of hybridization. Says Phillips, the people at the meeting were looking at the recovery plan’s goal of having 320 red wolves in captivity when Mech said he thought that number was too large and the cost too great for an animal that might not really be unique. Feeling there were still questions about its legitimacy as a species, he urged Ron Nowak and Barbara Lawrence to review the literature. If there were still disparate opinions about the identity of the red wolf, he believed the recovery team should resort to the new genetic analyses being conducted at the University of California at Los Angeles by Dr. Robert Wayne.
Wayne had collected blood and tissues from 276 gray wolves and 240 coyotes, sampling animals over the entire range of both species. He extracted from these samples bits of mitochondrial DNA. Mitochondrial DNA is a circular loop of DNA found outside the nucleus of a cell. Since it is outside the nucleus, it is inherited only along maternal lines. Unlike the DNA inside the nucleus, mitochondrial DNA is not responsible for physical characteristics like size or blood type or resistance to disease that determine a wolf’s fitness, so changes in it don’t increase or reduce an individual’s ability to reproduce. Because natural selection does not act upon them, mitochondrial DNA sequences evolve at rates five to ten times faster than the sequences in the DNA of a cell’s nucleus. So there is more variety in the mitochondrial DNA than in the nuclear DNA of any given species. That variety makes it useful for estimating how closely related individuals may be.
Wayne cut the mitochondrial DNA into small strips with restriction enzymes, which snip DNA strands between precise sequences of the four kinds of nucleotide—adenine, guanine, cytosine, and thymine—that make up DNA. He then looked at the sequence of nucleotides on the fragments. Theoretically, gray wolves would have one set of patterns and coyotes another.
The panel identified thirteen gray-wolf and twenty-four coyote genotypes, or patterns of DNA fragments. Coyotes had three times the genetic variety in their mitochondrial DNA, a finding that was consistent with the archaeological evidence that, as a species, the coyote is roughly three times as old as the wolf. But four of the wolf genotypes were found to be identical with coyote genotypes, and three other wolf genotypes were remarkably similar to coyote genotypes. Wayne concluded there had been at least six instances of hybridization, and that the genes from these matings had been widely disseminated among wolves in the Great Lakes region. He found coyote-wolf hybrids only in northern Minnesota, southern Ontario, and Quebec and on Isle Royale, but no coyote genotypes in wolves north of the present limits of coyote range. He found that coyote genotypes among wolves grew more likely as one moved east, that half the Minnesota wolves had coyote-derived genotypes, and that all the Quebec wolves sampled had them.
That study cast doubt on the purity of Isle Royale’s wolves, but it also seemed to Mech to offer a technique that could judge whether red wolves were hybrids. So Wayne and Susan M. Jenks, also of the University of California, undertook a study of mitochondrial DNA in red wolves and in coyotes. Taking samples of mitochondrial DNA from coyotes, gray wolves, and red wolves, they cut the DNA with restriction enzymes, as before, and compared the sequences of nucleotides in the fragments. The red wolves from four different lines of matrilineal descent had a single genotype, but that genotype was indistinguishable from a genotype found in two recent Louisiana coyotes. The finding strongly suggested hybridization.
In case the captives had only recently hybridized, Wayne looked at seventy-seven blood samples from animals taken during the 1970s. Morphological studies—studies based on the measurements of skulls—had classified 58 percent of these animals as coyotes, 31 percent as coyote-red-wolf hybrids, and only 11 percent as red wolves. But Wayne’s analysis classified 84 percent as having coyote genotype, 7 percent having a northern-gray-wolf genotype, and 9 percent a genotype characterist
ic of the Mexican wolf. Wayne also looked at six museum specimens of red wolf collected before 1930 and found them all similar or identical to coyote or gray-wolf genotypes. He found no sequence that occurred only in red wolves. “It suggested there was no red-wolf genotype,” says Wayne.
Wayne’s results questioned the accuracy of the nineteenth- and early-twentieth-century collectors. He believes most of the features Nowak selected in his study of red-wolf morphology related to size, and he thinks it likely that the earlier collectors used the same criteria. Nowak, he suggests, may simply be confirming earlier misidentifications.
Wayne confesses that his study does not amount to conclusive evidence that the red wolf originated as a hybrid. For one thing, the six skins from animals taken before 1930 could have been coyotes misidentified as red wolves by the collectors. “Toward the end of red-wolf range,” he says, “there aren’t many red wolves; there are lots of coyotes; and there is a great deal of phenotypic [or physical] variation among coyotes in that area.” Even if the blood samples and skins were indeed from red wolves, he could have missed distinctive sequences in the mitochondrial DNA in the course of slicing them up. Or the distinctive elements might have vanished from red-wolf mitochondrial DNA, possibly in recurrent periods of inbreeding in isolated packs long ago. But it is just as likely, he says, “that red-wolf phenotype [physical type, as opposed to genotype] could have derived entirely from hybridization between coyotes and red wolves.”
Wayne hopes to confirm his hypothesis by looking at the DNA of the cell nucleus. Nuclear DNA is harder to compare, because there is so much more of it, and so much of it is shared, not just among subspecies, but among creatures as disparate as humans and ants. But if one found sequences of nuclear DNA in red wolves that are not present in gray wolves or coyotes, it would establish that the red wolf is a valid species. And if one found coyote DNA in the nuclear DNA of red wolves, it would argue that the red wolf is a hybrid.
The Company of Wolves Page 22
