“I was dumbfounded how bad it was,” said Beschta. “Just dumbfounded.” The banks of the Lamar were barren, steep, and saw-edged. Soils that had been building for millennia had in recent decades been sluicing seaward with every rush of spring snowmelt and summer cloudburst. Few trees, no underbrush, no canopy, and no shade meant lost habitat for birds. It meant no more beavers that had once built ponds there, nor the flush of life that typically followed. “The stream,” said Beschta, “was falling apart.”
In better times and places, such streamside bands of life—the ecological community more formally known as riparian—otherwise constituted the bull’s-eye of biodiversity in the arid West. Composing a mere 1 percent of the landmass, riparian ecosystems harbored 80 percent of the West’s faunal diversity. That at least was the healthy riparian’s reputation. The river Beschta was watching in Yellowstone was something decidedly different. Something had happened to the Lamar over the last century that hadn’t happened there for many years before.
Beschta and many others believed that something was elk. The Northern Range of Yellowstone had for decades harbored one of the densest, most pampered populations of unfenced elk on the planet. Cervus elaphus, is an open-ground grazer and giant member of the deer family; some of the more massive bulls top seven hundred pounds. For nearly a century in Yellowstone they’d been protected from hunters and stripped of their native predators by federally backed trappers. The elk had responded by filling the Northern Range with a winter herd of twenty thousand, one of the densest populations known, whose ecological footprint had crushed the river bottoms and upland aspen groves, where the shoots and saplings of the forest’s next generation were perpetually pruned to the ankles.
In his travels Beschta had seen the same sort of dissolution throughout the overstocked range of the American West, where more than a century’s excess of cattle and sheep had pounded so many of the arid land’s foremost oases to dust. It had become so wearisomely familiar: mile after mile of rubbled streamsides, willow thickets rendered to nubs, denuded banks calving like miniature glaciers, the birds and beavers of yore all but gone. But it was especially unsettling to find the same sickness here in the heart of the nation’s flagship bastion of nature.
What Beschta could not see, even then as he stood vowing to return someday and unveil the unraveling of the Lamar, was a new order about to descend on Yellowstone’s ecology.
Coming Home
Seventy years before, near the spot where Beschta stood, two young wolves had simultaneously stepped, side by side, into steel-jawed traps. They were the last of at least 136 Yellowstone wolves killed during the nation’s eradication campaign. With their elimination in 1926, Yellowstone had become wolfless for perhaps the first time in the twelve thousand years since Canis lupus trotted in behind the retreating front of the Pleistocene glaciers.
Soon after ridding themselves of the wolf, the U.S. Park Service discovered another pest on their hands. Elk, the park’s antlered showpieces, amassed like locusts, chewing their way across the Northern Range. In times past, many among the great herds would migrate out of the park every autumn, descending from the Yellowstone Plateau to the valleys beyond, where the winters ran shorter and the snowpacks shallower. Many of those timeworn paths had since been blocked by ranch fences and gauntlets of hunters lining up just across the border. The elk began bottling up inside the park. Willow, cottonwood, and aspen, the arid West’s triumvirate of ecosystem-anchoring trees, began bearing the herd’s full weight.
By the late 1920s, biologists were voicing concerns that critical browse plants were disappearing, that soils were eroding, that unpalatable grasses were proliferating. “The range,” reported a team of scientists after visits in 1929 and 1933, “was in deplorable conditions when we first saw it, and its deterioration has been progressing steadily since then.”
The park service responded by trapping and transplanting and—when those labors fell short—shooting Yellowstone’s elk. Off and on for the next forty years the park’s administrators culled the Yellowstone herds, though to no discernable improvement of the range. Occasionally there came voices from without suggesting a more holistic approach, involving a more experienced class of hunter. Aldo Leopold obliquely broached this unmentionable in 1944, in a biting critique of the book The Wolves of North America. The book had ended on a disingenuous note from its coauthor Stanley P. Young, a career predator exterminator who suggested the country’s few remaining wolves be allowed a few places “to continue their existence with little molestation”—at which Leopold fairly detonated:
Yes, and so thinks every right-minded ecologist, but has the United States Fish and Wildlife Service no responsibility for implementing this thought before it completes its job of extirpation? Where are these areas? Probably every reasonable ecologist will agree that some of them should live in the larger national parks and wilderness areas; for instance, the Yellowstone and its adjacent national forests … Why, in the necessary process of extirpating wolves from the livestock ranges of Wyoming and Montana, were not some of the uninjured animals used to restock Yellowstone?
This was not a suggestion the managers of Yellowstone were racing to embrace, given how proudly they’d just ridded their park of its predatory vermin. Instead they redoubled their culling of elk, which lasted until the late 1960s, when local hunters raised hell and their congressmen threatened to pull the plug on the park’s funding. Yellowstone, in response, adopted a politically expedient form of nonmanagement, marketed as “natural regulation.” Old reports of elk damage were replaced with new ones blaming the failing aspen on changing climate and fire frequencies. The claims of overbrowsing and erosion were reexamined and declared exaggerations. The role of top predators was again dismissed as “a nonessential adjunct to the regulatory process.” Henceforth the naturally regulated elk went on an extended bender, multiplying to stratospheric new densities, and mowing down Yellowstone’s woodlands.
In 1973, Congress intervened again in the park’s ecological affairs, by a far more roundabout route. That year, President Nixon signed the Endangered Species Act, a law calling for protecting and restoring species facing extinction. The gray wolf of the Lower 48 was one of the first species named. And when biologists started listing those few special places that might still make a viable home for such a large, wide-ranging, pack-hunting carnivore of hoofed animals, one particular piece of real estate—with its nineteen thousand square miles of public land, centered by a national park bloated with thirty-five thousand elk—invariably rose to the top.
On January 12, 1995, after nearly a decade of environmental impact statements, court injunctions, raucous town meetings from Boise to Bozeman to Cheyenne, and nearly two hundred thousand letters and public comments, eight wolves—captured from the Canadian Rockies of Alberta and caged in aluminum shipping crates—were escorted by a caravan of patrol cars through the north gate of Yellowstone National Park. They rolled past a roadside lined with cheering schoolchildren, past TV crews and reporters, and onward out of sight, arriving at secret chain-link enclosures hidden in the hills above the Lamar Valley. Six more wolves arrived the following week and were taken to another pen above the Lamar. After a two-month acclimation period, the pens were opened. Within a week of leaving their pen, the Soda Butte pack had pulled down an elk calf. Wolves had come home to Yellowstone.
Biologists and wolf disciples of all stripes had long been waiting for the resurrection. The air above Yellowstone’s Northern Range droned with the propeller of a Piper Super Cub, radio antenna drawing daily fixes on the wolves in their wanderings. Crews of wolf researchers cruised the winding highway of the Lamar Valley, tracking the electronic blips emanating from the collar of every wolf in the park. Amateur wolf-watchers gathered in flocks on the hillside, monstrous scopes piercing the distances to the daily spectacles on display in the valley. Yellowstone had instantly become the wolf-watching capital of the world.
One of the hints of the daily miracles to expect came the wo
lves’ first year back in the park, when, with biologists watching and a movie camera rolling, two members of the Crystal Creek pack and a herd of elk put on a classic predator-prey clinic, from start to finish. The wolves’ pace was at first unhurried—a loping exploratory gait that was later likened to “sifting through the elk as a shepherd would through sheep.” One of the wolves found what it was looking for and sprinted headlong for a lone cow elk that was limping on a bad hind leg. The elk hobbled for the cover of the herd, but by then both wolves had singled her out. They cut the ailing elk from the herd, and the three took off across the valley flat.
A wolf is a long-legged endurance runner known for interspersing extended chases with sprints exceeding thirty miles per hour. And a healthy elk, as natural selection had decreed, tends to be yet a stride-length faster. But this was less than a healthy elk, and the wolves soon drew alongside, lunging for the neck. The elk shook them off, with forehooves flailing, trampling one of the attackers as she went. The wolf rolled and rejoined its packmate harrying the flanks, leaping and locking on with a bite force of sixteen hundred pounds per square inch. The elk faltered and fell, two wolves on her throat. She struggled to her feet, then fell again for the last time. Next day, biologists examined the kill, finding the elk’s ankle arthritic and “swollen like a melon”—an inherited flaw perhaps, which had just been weeded from the gene pool.
It was a textbook enactment of the wolves choreographed dance of death with their prey—the casual scanning of the herd, the targeting and testing for weakness, the escalation of the chase, the flailing of hooves and locking of teeth on hide, and the wrestling to submission.
The wolves had rapidly assuaged the biologists’ first concerns: They were feeding and mating and multiplying like mad, filling the predator void as fast as anyone had hoped or feared. Over the next ten years, the Yellowstone wolves spread to all corners of the park and spilled across the borders, south to the Grand Tetons and Wind Rivers, west to the Gallatin Canyon, east to the Absaroka Range, the population building to more than three hundred wolves across the Greater Yellowstone Ecosystem.
A feast of science, it would come to be called.
Hypotheses
What was known about wolves before Yellowstone had rested largely on a small handful of seminal studies, led by sturdy, woods-wise biologists toiling in lonely wilderness outposts in exchange for the rare glimpse of wolf society.
The first formal study of wolf and prey had been pioneered in Alaska, by the indomitable Adolph Murie. From 1939 to 1941, Murie hiked and climbed, dogsledded and skied thousands of miles through the vast tundra kingdom of Alaska’s Mount McKinley National Park (now named Denali), all for whatever hints he could gather of the hunting lives of McKinley’s wolves. The wolves’ main prey was the Dall sheep, a snow-white subarctic cousin to the Rocky Mountain bighorn. For all Murie’s Herculean labors, he observed but two live chases, neither ending in injury. But from what he could surmise from his crime-scene reconstructions of tracks and scat and blood in the snow, the wolves of McKinley worked hard for their living, chasing often and capturing seldom. The sheep, in their element among the rocky crags, sometimes toyed with their attackers. Murie once watched lambs a week old running circles around a wolf on a steep slope. He later found the sheep and the exhausted wolf lying fifty yards apart, the sheep dozing and resting and staring off in every direction.
In Murie’s classic recounting of his Alaskan adventure, The Wolves of Mount McKinley, predator and prey emerge as ecological players and evolutionary partners, smashing old stereotypes of the wolf as rabid agent of destruction.
It is my impression that the wolves course over the hills in search of vulnerable animals. Many bands seem to be chased, given a trial, and if no advantage is gained or weak animals discovered, the wolves travel on to chase the bands until an advantage can be seized. The sheep may be vulnerable because of their poor physical condition, due to old age, disease, or winter hardships. Sheep in their first year also seem to be specially susceptible to the rigors of winter. The animals may be vulnerable because of the situation in which they are surprised. If discovered out on the flats the sheep may be overtaken before gaining safety in the cliffs. If weak animals were in the band, their speed and endurance would be less than that of the strong and they would naturally be the first victims …
The possibility is generally recognized that through predation the weak and diseased are eliminated, so that in the long run what seems so harmful may be beneficial to the species. Perhaps the evolution of the mountain sheep has progressed to a point where it is in equilibrium with its environment but still requires environmental stresses such as the wolf to maintain this equilibrium.
Murie’s prescient observations in Alaska would echo thirty years later at an unplanned predator lab anchored fifteen miles off the northwest shore of Lake Superior. Isle Royale had been pioneered by moose around the turn of the twentieth century and by wolves fifty years later, the former supposedly swimming from the mainland, the latter crossing on a winter bridge of ice. In 1958, a Purdue University grad student named L. David Mech began what has since become the longest-running study of wolf and prey. What Murie had postulated about the wolves of Denali, Mech and a succession of students confirmed at Isle Royale: Wolves killed neither randomly nor easily. Of seventy-seven moose that Mech saw tested by wolves, seventy-one walked away.
In time, Isle Royale also buttressed Murie’s postulate that the wolf’s impact extended beyond its immediate prey. Mech’s most venerable successor, Rolf Peterson, and a colleague Brian McLaren measured the tree rings of balsam fir on Isle Royale, a prime winter moose food. The rings, layers of wood laid down during the growing season, measured wider in good years, thinner in lean years. If a hungry moose were to camp beside a balsam fir, the stress of being eaten would be gauged in the tree’s razor thin growth ring the next season. When McLaren and Peterson compared the varying widths of the tree rings with the fluctuating number of wolves in the island, they uncovered an uncanny synchrony. More wolves, fewer moose, fatter rings, went the explanation. “When wolf numbers were high, the forest grew,” Peterson exclaimed. “What an impressive achievement for a couple of dozen wolves that were just doing what comes naturally!”
From Isle Royale came the realization that the wolf was something more than a weeder of weak moose. It was a force of the forest. And that was a notion that Yellowstone, not long into its own experiment with wolves, was about to validate in spates.
A New Order
What Murie and Mech had learned through hard hours of slogging for murky glimpses through trees and postmortem reconstructions of ripening carcasses, Yellowstone not uncommonly offered up in living Technicolor from the roadside. With the throngs watching, the cameras rolling, and a naked clarity unmatched by any wolf terrain in the world, the wolves and elk of the Lamar acted out their parts—the predators methodically testing and selecting, chasing and attacking, sometimes killing, more often passing; the elk in their turn trotting and galloping, confronting and kicking, sometimes dying, more often escaping, and occasionally killing their would-be killers.
Much as the contests between wolf and elk dominated the highlight reels, no one creature so drastically reflected the wolves’ return as the coyote. Better known in leaner environs as hunters of rodents and rabbits—more famously painted by Mark Twain as “a slim, sick and sorry-looking skeleton … a living, breathing allegory of want”—the coyotes of Yellowstone had developed into a different animal during the wolves’ seven-decade absence. They had taken to forming big packs, killing elk calves, and occasionally, when emboldened by deep snow, tackling grown elk. They were seen stealing kills from mountain lions. Left alone in the land of giant prey, the coyotes had gone wolfish. This made for some interesting reunions when the lords of the house finally came home.
With the wolves’ return, Yellowstone’s coyotes were quickly reeducated on top-dog protocol. Those caught trespassing in wolf territories were chased down and torn apart. Wit
hin three years of the wolves’ reoccupation, the coyote population of the Northern Range had been halved.
As dim as life had become for the demoted coyote, it had brightened for those the coyote had once terrorized. For the first time in more than a decade, the park’s precarious herd of pronghorn antelope began to show signs of life.
The pronghorn, hoofed rocket of the West’s open spaces, had been nearly annihilated by market hunters a century before. It had then made a celebrated comeback over much of its native range. Yet for puzzling reasons, the pronghorn had been suffering an unusually tough time surviving in the supposed sanctuary of Yellowstone. Their difficulties, it turned out, had much to do with the Yellowstone coyote. By observing pronghorns late in their pregnancy, the coyotes of Yellowstone had learned not only to take pronghorn fawns within hours or days of birth, but also their mothers as they defended them. In the first year that pronghorn biologist John Byers began watching the proceedings in the northwest corner of Yellowstone, seven mother pronghorn were killed within the first week of parturition. The average lifespan for the fawns was six days.
Meanwhile, eastward in the valley of the Lamar, life for the pronghorn was taking a good turn. In the thick of the densest concentration of wolves on the planet, the fawns of Lamar were surviving with baffling success. Byers’s explanation was this: While the wolves of the Lamar were busy running down elk and trespassing coyotes, the pronghorn of the Lamar were busy raising fawns beneath their noses. At the end of his field season, Byers concluded, “It’s likely wolves are going to be the single-most important force to save the pronghorn of Yellowstone.”
Where the Wild Things Were Page 16