What drives the wolverine's seemingly insatiable need to stay on the go?
- Stephen Stuebner
- Oct 01, 1997
From the window of a low-flying Cessna, Jeff Copeland spied a set of wolverine tracks leading over a 10,000-foot pass in the high peaks of the Frank Church-River of No Return Wilderness. A gentle grin creased his face as he looked over at the pilot, shaking his head slowly. Once again, the mysterious behavior of the wolverine hits the research wildlife biologist in the gut.
It never ceases to amaze me when I'm flying and I see a set of tracks in the snow in the highest, most rugged country in the wilderness," Copeland says. "What in the world is that creature doing up there?"
For three years, Copeland tried to uncover the clues behind the mysterious behavior of wolverines in central Idaho. Funded by the U.S. Forest Service and Idaho Fish and Game Department, the project yielded quick dividends, documenting for the first time that a viable population of wolverines exists in the immense wild and gnarly mountainous core of Idaho. But attempts to continue the project hit a snag: Authorities could not come up with the money to fund further wolverine research by Copeland.
The financial crunch came at a crucial time in the history of efforts to understand the behavior and range of this enigmatic beast. It also came just a year after Copeland caught two wolverine kits and implanted transmitters in them--an unprecedented feat that would have provided more insight into wolverine behavior than anyone knew before. "It's really disappointing," says the scientist, who now works for the Idaho Fish and Game Department. "We were on the verge of discovering some really important aspects of wolverine behavior."
To this day, a radio-collared wolverine may be beeping away and no one is listening. Meanwhile, much of the species' behavior and habits remains a mystery.
While Copeland discovered healthy numbers of wolverines in Idaho, biologists have come up empty in other plausible mountain locations, such as southwest Colorado, the Northern Cascades in Washington and the High Sierra in Nevada and California. Somehow, small wolverine populations hovering on the edge of their historic range have been inexplicably dying off over the last 20 years. Since so little research has been done on the notoriously secretive critters, no one knows for sure if they ever existed in significant numbers in these edge areas to begin with.
Alarmed by the declining population trend, two nonprofit groups--the Biodiversity Legal Foundation in Colorado and the Predator Project in Montana--together filed a petition in March 1995 calling for federal protection of the wolverine as either threatened or endangered in the lower 48 states under the Endangered Species Act (ESA). That petition was rejected soon afterwards by the U.S. Fish and Wildlife Service (FWS).
The petition contained little documentation of threats to the wolverine overall or to a significant portion of its contiguous United States range," commented FWS authorities in their rejection. "No substantiating data was provided to demonstrate that the asserted threats had resulted in a significant decline in wolverine numbers." Even if the agency wanted to list wolverines, Congress had placed a moratorium on new ESA listings in 1995 and 1996.
Nevertheless, the Biodiversity Legal Foundation filed a lawsuit challenging the FWS decision. While the outcome of that case is pending, the FWS rejection of the wolverine petition underscores a classic dilemma facing conservation groups and the agencies charged with protecting wolverines: The dearth of research information about the creatures makes it difficult for federal officials to justify a listing, or provide insight for setting management guidelines to protect wolverines and their habitat.
National Wildlife Federation senior scientist Steve Torbit believes that the jury is still out regarding whether or not wolverines should be listed. But he is concerned about losing wolverines that live on the edge of their historical range. "Those animals may be the most valuable, genetically," says Torbit, who once searched for wolverines in southwest Colorado. "Living at the edge, they are more likely to develop important behavioral or physical adaptations to help them survive."
One way to help save the remnant wolverines, Torbit suggests, is to do a population status review. "The first thing that should be done is to conduct a search for wolverines in the most promising and intact habitat areas throughout their historical range," he says. "The information from such a search would enable us to factor wolverines into the land management equations." Until such research is completed, some wolverines may continue to live a precarious existence as human development encroaches on their habitat.
Long the focus of legend and mythology, the wolverine is the largest North American member of the weasel clan, or Mustelidae family. Although big males rarely exceed 40 pounds, the animals are equipped with grizzly-bearlike vocal cords--a handy defensive bluffing device that scares away larger predators. "Ferocious-sounding beasts, aren't they?" observes Jeff Copeland.
Wolverines are primarily opportunistic scavengers, particularly during the colder months when they feed on mostly winter-killed carrion. In contrast to pack animals such as wolves, which follow big-game herds to winter ranges for a dependable food supply, wolverines are more solitary creatures that can travel dozens of miles in a matter of days, up and over multiple peaks and ridgetops in search of food.
Copeland kept a running count of his wolverine sightings during airplane flights on a large map of Idaho on corkboard . The map encompassed 3,000 square miles. In following 10 to 12 radio-collared wolverines over the course of three years, he recorded more than 800 sightings. The pins are scattered throughout central Idaho, reflecting animals that cruised immense distances for food, but also the dispersal of young adults in search of a new home range. Sometimes the creatures came back to their original range; sometimes they were never seen again.
Copeland continues to be baffled by how far they travel. "It's just never ceased to amaze me how far these animals go in a short period of time," he says. "The hallmark of the wolverine is probably its insatiable need to be on the move." The scientist found that several young males in his study traveled at least 125 miles in their dispersal movements.
Historical and fossil records indicate that the most extensive populations of wolverines were--and still are--found in Alaska and Canada. Lesser numbers fanned out in peninsular fingers down into the Cascades, High Sierra, Northern Rockies, Central Rockies, even into Arizona and New Mexico. The historical records indicate that wolverines also existed in a number of midwestern and eastern states. Although the University of Michigan claims the wolverine as its sports mascot, a 1995 scientific paper on the species in the journal Mammalian Species indicates that the animals never resided in that state.
The physical makeup of wolverines--particularly their strong jaws and large incisor teeth--enhance their ability to chew on bones. Their vicelike jaw muscles sometimes enable wolverines to chew their way out of traps or cages.
Wolverines also have a potent sense of smell and effective scent-marking abilities--tools they employ to sniff out and mark food. In his fieldwork, Copeland discovered partially eaten food caches that wolverines apparently left for themselves underneath deep snow. Wolverines may be capable of digging down through six feet of snow to feed on marmots and hibernating rodents.
Because wolverines are scavengers and poor direct killers, they have been known to starve to death. Combine that with a low reproductive rate--usually two kits a year, sometimes none--and it is easy to see why wolverine populations have never reached high densities. As scavengers, wolverines are easily attracted to baits. The animals gained the nickname "the Evil Ones" from Eskimos in Alaska, because of their habit of raiding animal traps.
With most wolverine field-research funds dried up for now, land-management and wildlife agencies in the West are stuck with trying to devise management guidelines for the animals without much to go on. Currently, they are relying heavily on the efforts of the Western Forest Carnivore Committee, a combination of university scientists, state and federal biologists and researchers from nonprofit conservation groups that was put together in the late 1980s. The committee shares information on wolverine, lynx, fisher and marten studies throughout western North America to determine the best management strategies for these predators.
At the core of the committee's recommendations is the need for maintaining wild and undisturbed territory with a low frequency of human contact, particularly during the spring denning period. Bill Ruediger, chairman of the Carnivore Committee and program leader for threatened and endangered species for the Forest Service's Northern Rockies Region in Missoula, Montana, points out that historically, "wolverines were probably decimated by predator-control programs and trapping at the turn of the century. Now, our biggest concerns are loss of habitat and major habitat fragmentation such as highways crisscrossing the animals' range. The effects of such fragmentation are the isolation of local populations and eventual loss of these carnivores, mountain range by mountain range."
Another problem facing the wolverine and other forest carnivores, says Ruediger, is that state and federal agencies "have not successfully pulled together a broad-scale conservation strategy for protecting and managing the species." The scientist is concerned that the wolverine has already vanished from many of its former haunts in eastern Canada, the California High Sierra, the Colorado Rockies and the Oregon Cascades. "The Northern Rockies," says Ruediger, "may be the animal's last major domain in this country."
NWF's Torbit reiterates that the federal and state agencies cannot effectively manage for the needs of wolverines "when no one knows the extent of their range or their specific habitat needs." Legal Foundation Director Jasper Carlton, meanwhile, believes that no wilderness study areas should be logged until more is known about wolverine habitat needs.
Again, this is the classic dilemma of insufficient information. "I believe the Forest Service and other agencies are doing what they can to manage for wolverines," says Ruediger. "But the fact remains that we still have more questions than answers. I mean, what kind of animal is it exactly?"
Though his project came to a premature halt, the same question continues to haunt Copeland. After chasing and observing wolverines for years, he is now under the creatures' spell. The scientist remains particularly intrigued by the wolverines' wide-ranging, scavenger-predator behaviors. "Arguably," he says, "they're a different sort of a beast than anything else traveling out there."
Idaho writer Stephen Stuebner spent several days in the field with wolverine scientists while reporting for this article.
Forest Carnivores: NWF Takes Action
As part of its efforts to protect wolverines and other small western carnivores, NWF was instrumental in the creation of the Western Forest Carnivore Committee. NWF is now actively involved in several forest-habitat programs through its regional offices in Oregon and Montana. "Our campaign to reform road building in national forests is aimed at solving one significant habitat-intrusion problem," says NWF biologist Mike Roy. To stay informed on matters relating to western carnivores, write: NWF, Northern Rockies Project Office, 240 N. Higgins, Missoula, Montana 59802.