On the Edge
Wolverines, long admired for their ferocity and canniness, are so elusive that few people have even seen one. Now biologists are racing to find them before trappers do.
Two hours of digging in 10-foot-deep snow reveals a multi-layered maze of tunnels extending across a 90-by-150-foot stack of avalanche debris. An exasperated Inman calls off the dig. "Even if she's in there, we'd never find her today," he says, a soft Tennessee accent tracing his disappointment.
His crisp blue eyes lift to the band of cliffs rimming the cirque, lipped in 20-foot blue cornices. "If an adult wolverine was standing here and wanted to go up and over that ridge," Inman asks McCue, rhetorically, "what would it take her, 10 minutes? Fifteen?"
It would take us until tomorrow, and by then she'd be somewhere else.
Jim Halfpenny, a noted tracker and naturalist, once told me he knew a trapper who has, over his lifetime, killed 30 wolverines in southwestern Montana. That would be a remarkably destructive feat--one man wiping out a significant number of the wolverines born in that area in his lifetime. In the northern Rockies, fewer than 10 wolverines--a dominant male, two or three breeding females, a couple of the year's young, and the occasional interloping male--might occupy 300 to 500 square miles or more. Trapping could take a heavy toll on such a meager population.
Jeff Copeland, a biologist with the U.S. Forest Service's Rocky Mountain Research Station in Missoula, Montana, has been studying wolverines in the contiguous United States longer than anybody. He currently oversees monitoring projects in Glacier and Yellowstone national parks, which, together with work done by Keith Aubry, a biologist for the Forest Service, and Inman, are the only ongoing wolverine studies in the country. Another research project, in Montana's Big Hole Valley, fizzled--at least partly because recreational trappers killed 40 percent of the animals in the study.
Copeland says both he and Inman have demonstrated that recreational trapping can have a "huge impact" on wolverine populations. "It's pretty clear that areas that are trapped experience higher mortality," says Copeland. "It's not like the population can compensate for it."
But when Montana officials publicly discuss regulations or limitations on recreational trapping of any sort, a cadre of trappers show up to shout about their heritage. At an August 2007 meeting of the state's Fish, Wildlife, and Parks Commission, for instance, Inman testified that wolverine quotas should be cut almost in half from the current 12 to no more than seven animals taken statewide. He also offered the commissioners the opportunity to review data with him and learn why, in the case of wolverines, these small numbers matter. Swayed by the trapping lobby, the commissioners seemed concerned, then reduced the quota to 10, just two fewer than the original allowance.
Another wolverine search, another day, this time in the high mountains around Yellowstone National Park. (All of the biologists involved in this story asked me not to identify drainages we visited, for fear trappers may come looking for wolverine pelts.) This time I'm with Jason Wilmot, a tall, steely-blue-eyed man with cornsilk blond hair who works for Copeland on a study in the Yellowstone park environs. Nobody is sure how many wolverines use the park as their home range, but Wilmot knows of at least two.
He and I are checking a "lid down" signal being sent by one of the live traps--log houses six feet long by three feet wide and four feet deep, built with a trapdoor roof that slams shut once a scavenger is lured in by the frozen beaver carcasses used as bait--he's built just outside the park. When we tilt up the lid and peer in with a flashlight, a red fox squints back at us--no wolverines for me on this day either. Which, Wilmot tells me, I should accept as par for the course.
"Wolverines are such a mystery. They exist on the edge of human understanding, even comprehension. They're so tough and live in such extreme terrain. People have spent their whole lives in Montana outdoors and never seen a wolverine," marvels Wilmot, who has spent a good chunk of his life studying wolverines and seen only seven when he wasn't conducting research. "We're still trying to find out foundational information, basic ecology. What's their reproduction rate, what do they eat? It's amazing to me that there's a critter in this day and age that we know so little about."
Above us on the steep mountain slopes, snowmobile tracks loop in parabolas, the remnants of an activity called "high marking," in which riders drive their snowmobiles as high as they can up a steep pitch. "They're getting in touch with nature," Wilmot says with a twinge of sarcasm. Today's snowmobiles are faster and more powerful than ever before, carrying riders deeper and deeper into wolverine country.
If you drew a line on a map around areas where deep snow persists late into May, you would fairly accurately describe the wolverine's known historical range: the circumpolar tundra and boreal forests; Alaska and western Canada; the island refugia in the northern Rockies; the Cascades range in Washington and Oregon; the upper Great Lakes; and California's Sierra Nevada range, where a long-isolated population genetically more similar to Mongolian and Scandinavian animals than their North American cousins has probably--nobody knows for sure--been extirpated. That line would also encompass some prime winter recreation areas.