With the winter of 2005–6, the skeptics got their wish. It was a deep, classic Yellowstone snowpack, a difficult time for elk turned deadly with abnormally high temperatures that turned the snow to concrete. As the elk went hungry trying to paw through to the upland grass, they turned heavily for the bottomland willow. By logic of the hard-winter hypothesis, the willows should have taken a beating, the elk’s pain of hunger trumping their fear of wolves. If such a blip of bad weather could crush Yellowstone’s recovering riparian, it would do likewise to the wolf hypothesis.
Among those watching, Bill Ripple was more than anxious for the answer. That summer he hurried out to see for himself.
He came back with a smile. “The willows are doing just fine,” Ripple reported. “Actually, they’re continuing to grow.”
“I guess the point I’m making,” said Duncan Patten, a veteran riparian biologist of the Yellowstone ecosystem and prominent opponent of the wolf bandwagon, “[is] there’s a multitude of factors that control how willows do. I’m not discounting wolves. But I don’t think they’re the bottom line. They’re part of the equation. At this point, put me on the side of the equation as the doubting Thomas. We really won’t know for decades how this is going to shake out.”
Patten’s doubts were echoed by a few who had been focusing their attentions on the predatory act itself, and wondering themselves if the fear factor had indeed been overblown. These were not grasshoppers or chipmunks facing inescapable death in the clutches of a spider or raptor. These were powerful, quarter-ton adversaries kicking and butting and otherwise having much to say as to whether and when they would be wolf food.
Daniel MacNulty, a young researcher dedicated to deciphering the attacks, had been observing the elk as anything but helpless meat on the hoof. Tracking the wolf hunts by truck and on skis, camping in igloos for weeks at a time in Yellowstone’s backcountry, poring over attack films frame by frame, MacNulty dissected what had come to be called the dance of death between wolf and elk. The dance was a finely choreographed ritual between attacker and defender, proceeding through a series of predictable steps, each one escalating in intensity, from the ear-pricking moment of detection to the final throttling gasp of death. Rarely, on average, did the dance follow to conclusion. The elk in their meetings with wolves had a way of immediately announcing who was boss.
An elk with speed to burn would throw its head high and break into an exaggerated trot, or stiffly bounce into a four-legged pogo gait called stotting. Either gait was far slower than galloping. Both were akin to an Olympic miler looking back on the field and skipping into a schoolgirl’s hopscotch. “Chase me if you choose” was the heart-strong elk’s message to the wolf, “but in the end, you will be the more tired and hungry for the effort.”
Even to catch an elk was no guarantee of success. This was when wolves sometimes died on the receiving end of a well-placed kick or thrust of an antler. Which said nothing of the perils involved when wolves took to tackling bison. Although nine of every ten animals killed by wolves in Yellowstone were elk, a few wolf packs had taken to specializing on the most formidable prey in the land. After watching what a three-quarter-ton bison bull could do to a one-hundred-pound wolf, one had to wonder why. The battle of the decade was caught on film in Yellowstone’s remote Pelican Valley, an epic struggle between an old bull bison cornered by deep snow and seven members of Mollie’s pack. The bull was like a giant boulder, with a neck as thick as a pier piling. Its head amounted to a horned battering ram, its hooves packing power to splinter skulls and pulverize internal organs. Mollie’s pack, for its part, was a hulking gang, composed of exceptionally large wolves that had chosen the kamikaze’s life in the most brutal environment of Yellowstone. MacNulty was watching, and filmmaker Bob Landis’s machine was rolling as the wolves attacked fore and aft, biting at the flanks, grabbing for the nose. Horns and hooves sent wolf bodies flying like rag dolls in a fight that lasted from dawn to dusk and on into the night. The light of the next morning revealed the old bull dead. And Mollie’s pack wasn’t faring much better. Three of the attackers were limping, and a fourth lay curled beneath a spruce, soon to die with a broken leg and untold internal injuries.
Over the first ten years of the wolves’ return to Yellowstone, eight other wolves would die in predatory battle, seven from the antlers and hooves of elk, and the eighth in a losing battle with a moose. “But one thing that’s underestimated, and I believe it’s common,” said Doug Smith, “is injuries. We don’t have any good tally of injuries, but frequently we see wolves limping.” For every five elk attacked by wolves in Yellowstone, four would win their contest. Fearful though it may have seemed to be prey in wolf country, one had to wonder—as MacNulty and his fellow skeptics wondered—whether the inverse might have better captured the essence of Yellowstone’s wolfdom. Amid such fierce prey, a trophic cascade was no trivial matter for a wolf pack to trigger.
Smith himself had arrived in Yellowstone as a bit of a skeptic. He had been there from the start of Yellowstone’s modern wolf era; he had helped carry the first wolves to the holding pens and cut the holes that turned them loose. He had come with thirteen years of experience on Isle Royale, training ground for some of the wolf’s greatest students, gathering data on balsam fir and moose and the most famous wolf cascade on record. Along the way, about every five years or so, he had also seen a succession of pet theories tossed on Isle Royale’s scrap heap. Wolves in control one year, a hard winter the next, a debilitating infestation of ticks after that. As much as Isle Royale had greased the skids in Smith’s mind toward believing in a Yellowstone wolf cascade, it had also infused a measure of trepidation for the quick and appealing conclusion.
But as Smith tracked his wolves through Yellowstone, every week without fail for the next thirteen years, the wolves softened his doubts. “You begin to get an intuitive feel for what’s going on,” said Smith. “You follow wolves, you hike and ride and ski and fly, day in and day out in the same country they use. You begin to get these scientific hunches.”
Smith’s hunches increasingly, if cautiously, credited wolves as essential conspirators in Yellowstone’s revolution. As the mortality statistics began pouring in from radio-collared elk the facts began to back the fear theory. The edges and incongruities of Yellowstone’s landscape had indeed become particularly dangerous places in a land patrolled by wolves. Plotting the places where the elk had died over the years, the dots on the map clustered along the drainages. And that was a phenomenon that Smith, from his hours aloft in the Super Cub, could personally confirm.
“I’ve seen hunts on the flat and even terrain where the elk turn on the jets and outrun wolves, unless there’s something wrong with them. But I’ve seen other times where the elk is beating the wolves, they hit a stream course, and the wolves close the gap. When you weigh five hundred pounds, you have to slow down more. And when wolves hit that incongruity, they slow down less. They close the gap. The elk is coming out of the other side of the drainage, and that’s when the wolf gets its teeth into the hindquarters, and that’s when the battle begins.”
What Ripple and Beschta had surmised from reading thousands of browsed twigs and measuring saplings sprouting along the stream banks, Smith had come to understand by chasing the tails of the wolves themselves. By the end of his first decade with the wolves of Yellowstone, Smith was on record as one of the believers. As he would often say, “In the decades to come, wolves may prove no less fundamental to the life of Yellowstone than water is to the Everglades.”
Whatever the homecoming wolves had done for Yellowstone, they had positively sparked the imagination. In those patches of sprouting willows and aspen and resurgent cottonwoods, conservationists envisioned an antidote to the long malaise of the western rangelands and waterways. They imagined trees taking root, sloughing banks taking hold, shade spreading from the flourishing groves over the water’s edge. Fish and aquatic insects would return to the sheltered shallows, warblers to the willows. Beavers would come and
build their dams, their ponds punctuating the hurried water, with fish and amphibians, muskrats and mink, following in the wake. They imagined the West’s hoof-beaten oases reborn. And jump-starting the revival, if the preliminaries held true, was as simple—and as difficult—as plugging the missing predator into the picture.
“Biodiversity is the big deal, and sustaining it is huge,” said Beschta. “It’s something in my career I would never have guessed: that wolves would control the character of rivers. It’s something I’ve worked on all my life—streams and rivers. And here it is this four-legged critter doing it. It’s pretty amazing. Wolves controlling rivers.”
NINE
The Lions of Zion
BY THE END of the first decade of wolves in Yellowstone, aspens were sprouting by the thousands, willows were going gangbusters, and beaver were returning to secluded reaches of the Yellowstone watershed, all for the first time in at least half a century—all in suspicious synchrony with the return of Yellowstone’s wolves
The shaky limb that Ripple and Beschta had ventured upon had grown sturdier with time. With every new announcement of their latest findings, Ripple and Beschta waited and listened for the professional rebuttals—some new evidence or critique, some out-of-the-blue broadside that would cripple their argument. And on they waited.
Waiting was an activity Ripple and Beschta had learned to practice on the move. The question, to their minds, was no longer whether wolves bolstered the diversity of life in Yellowstone, but what that result heralded for the rest of the country. Canis lupus had gone from nationwide resident to a half dozen pinpoints on the country map, leaving grand swaths of wolfless terrain.
Their curiosities led them far beyond wolves and willows. From the aspen groves and riverbeds of Yellowstone, Ripple and Beschta journeyed back to the historical roots of top-predator ecology. They found themselves tracing the literary trail from the heretics Hairston, Smith, and Slobodkin, whose green world hypothesis in 1960—suggesting a planet kept that way by predators—had touched off a half-century war of ecological worldviews. They passed through the Olympic Peninsula of Robert T. Paine, chronicler of the sea star Pisaster as keystone predator of the rocky shore; to the Aleutian kelp forests tended by James Estes’s sea otters; to Michael Soulé and the bird-guardian coyotes of Southern California. They noted the urgent new warnings from Venezuela, where John Terborgh’s predator-free archipelago was in the throes of ecological meltdown.
Along the way, they continually crossed paths with Aldo Leopold, the father of wildlife management, and latecomer champion of deer-eating carnivores. Long before Bob Paine had coined the term, the trophic cascade concept had become Leopold’s cause célèbre in his crusade to save America’s deer-bitten forests. He brought stories of sterility from the fangless woods of Germany, starvation from the deer yards of wolfless Wisconsin. In the early 1940s, he and several colleagues started pulling together the histories of more than one hundred ungulate populations across the United States, noting a recurring sequence of predator eradication followed by exploding populations of their prey and ruination of their range. Irruptions, Leopold called them. “We have found no record of a deer irruption in North American antedating the removal of deer predators,” he wrote.
Conversely, wherever large carnivores had been suppressed, the forests and range had been preyed upon. “Thus the Yellowstone has lost its wolves and cougars, with the result that elk are ruining the flora, particularly on the winter range,” wrote Leopold in A Sand County Almanac, fifty years before scientists counting tree rings confirmed the fact for themselves.
History abundantly confirms that Leopold, as poetic defender of predators, was largely ignored by those in charge. What it less often mentions is the meaner face that Leopold had once worn in life. This was the man who, in 1919, as a brash greenhorn forester in New Mexico and editor of his own newspaper, had written, “Good game laws well enforced will raise enough game either for sportsmen or for varmints, but not enough for both … It is most emphatically a reason for going out after the last lion scalp, and getting it.”
This was the man who twenty-five years later had turned about-face, penning the century’s most celebrated paean to top predators. In the essay “Thinking like a Mountain,” Leopold recalled himself as that young hair-trigger ranger in New Mexico, at the dying side of a bullet-riddled wolf whose young family he had just helped ambush.
We reached the old wolf in time to watch a fierce green fire dying in her eyes. I realized then, and have known ever since, that there was something new to me in those eyes—something known only to her and to the mountain. I was young then, and full of trigger-itch. I thought that because fewer wolves meant more deer, that no wolves would mean hunters’ paradise. But after seeing the green fire die, I sensed that neither the wolf nor the mountain agreed with such a view.
Kaibab
Of all the irruptions that Leopold heralded, one became his crusading banner. It was a horrific tale of meteoric rise and smoldering crash. It was one he never actually visited until long after the rubble had cleared. Yet the leg-end of the Kaibab, the most infamous deer disaster in history, was a legend largely built by Leopold.
The Kaibab Plateau is an eleven-hundred-square-mile block of earth thrust high above the arid canyonlands of northern Arizona. It is an island wilderness, bounded northward by Utah desert, southward by the mile-deep plunge of the Grand Canyon. The Paiute people named the plateau Kaibab, a “mountain lying down.” The Kaibab is a displaced piece of northern Montana in Arizona, where snowstorms are not unexpected in May, where the summers are famous for shady parklands of pine and green meadows and flowerings of rhapsodic verse: “We, who through successive summers have wandered through its forests and parks, have come to regard it as the most enchanting region it has ever been our privilege to visit,” wrote the geologist C. E. Dutton in 1882. “There is a constant succession of parks and glades—dreamy avenues of grass and flowers winding between sylvan walls or spreading out into broad open meadows. From June until September there is a display of wild flowers quite beyond description.”
There was also once a conspicuous herd of mule deer upon the Kaibab, for which the plateau was set aside as a game preserve in 1906. Henceforth, deer hunters were banned, and deer predators were exterminated. Over the next twenty-five years, some six thousand carnivores were trapped and gunned off the Kaibab, including eight hundred mountain lions and the last thirty of its wolves. The deer in turn went on a tear. Estimates of the Kaibab herd leaped from four thousand to one hundred thousand.
The Kaibab became country where tourists in their motorcars came at dusk to marvel at deer meadows packed by the hundreds, while naturalists viewing the same scene began counting down to catastrophe. As the browse lines crept higher up the trees, desperate deer started tiptoeing on hind legs for the last edible twig.
In his 1949 novel, The Deer Stalker, the western writer Zane Grey laid out as good a rendering of the classic Kaibab account as any historian since. Building to the irruptive climax, Grey’s character Jim Evers—based on the hunter Uncle Jim Owens, who was credited with having shot six hundred mountain lions off the plateau—ironically sums up the ecological bunglings that have led the deer to the brink. “I’ve seen this deer herd grow from five to fifty thousand … Wal, killin’ off the varmints, specially the cougars, has broken the balance of nature so far as these deer are concerned. Herds of deer, runnin’ free, will never thrive whar the cougars have been killed off… They just eat up everythin’. An’ now they’re goin’ to starve or die of disease.”
On the eve of disaster, a plan is hatched. The scheme is to hire a posse of cowboys and a line of Indians to drive deer by the thousands off the plateau, down the walls of the Grand Canyon, across the roaring Colorado River, then back up the other side to richer pastures on the South Rim. Most incredibly of all, Grey is not making any of this up.
The plan was not fiction. Nor did the deer turn out to be as witless as cattle. They reversed through the dri
vers, turning cowboys into Keystone Cops, as they bounded back into the Kaibab forests from which they’d come.
The comedy ended there. The following two winters, without ever stepping foot near the canyon, the deer took the dive that many had feared. In the winters of 1924 and 1925 they starved en masse upon the plateau. Hunters were later called in to foreshorten the misery. Within six years, the Kaibab herd had fallen by eighty thousand.
The moral that emerged from the Kaibab spoke of the madness of eradicating predators as a means to more deer. As Evers drawls in The Deer Stalker, “Men cain’ remove thet balance an’ expect nature to correct it.” Or, as expressed in the King’s English by the British ecologist Charles S. Elton in his 1927 classic Animal Ecology, “Here it was clear that the absence of their usual enemies was disastrous to the deer … for the deer as a whole depend on them to preserve their optimum numbers and to prevent them from over-eating their food-supply.”
Aldo Leopold was nowhere near when the Kaibab herd imploded, but he would not escape the tremors. At an international biological conference in Labrador in 1931, Leopold befriended the eminent Elton, and soon thereafter was subscribing to Elton’s pyramidal view of life, the one founded on those many, many plants at its base and topped by those very few big carnivores at its apex. Leopold pondered the Eltonian pyramid, contemplating the consequences when “larger predators are lopped off the apex … The process of altering the pyramid for human occupation releases stored energy, and this often gives rise, during the pioneering period, to a deceptive exuberance of plant and animal life, both wild and tame. These releases of biotic capital tend to becloud or postpone the penalties of violence.”
As Leopold began gathering the stats for his 1943 paper on deer irruptions, he came upon another fascinating pyramid of sorts, this one drawn by D. Irvin Rasmussen, a gifted young naturalist who for his dissertation had spent two summers absorbing the ecology of the Kaibab. Rasmussen in his write-up illustrated the deer debacle as a steep mountain, their numbers rising sharply following the extermination of cougars and wolves, their numbers then falling sharply toward the infamous crash that left one out of ten deer standing. Leopold lifted and embellished Rasmussen’s graph for his irruptions paper. And for half a century thereafter, the Kaibab legend, as told by Leopold, was gospel. By the 1950s, rarely a biology textbook was published lacking the Kaibab disaster as a lesson in man’s ham-handed tinkering with mother nature’s sense of balance. Hairston, Smith, and Slobodkin used the Kaibab as one of the anchors in their green world argument. Rachel Carson’s Silent Spring, the most influential environmental book of the century, included the classic Kaibab story as proof of “the dire results of upsetting nature’s own arrangements.”
Where the Wild Things Were Page 18