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The Yellowstone We Don't See: A Struggle of Life and Death

Part two in our series on the park takes us into the backcountry, where predator and prey form a delicate balance in a great ecosystem.

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A lone member of the Phantom Springs wolf pack stands tall in Grand Teton National Park. After an absence of about 70 years, wolves returned to the park in 1998, when they moved down from Yellowstone. 
Editor's Note: This is the second of a three-part story, appearing in the May 2016 issue of  National Geographic magazine.  Return to part one, read  an abridged version, or find more at  natgeo.com/yellowstone

In 1995 and 1996, some 70 years after Yellowstone’s last wolf howled its last howl, 31 wolves from western Canada were released from acclimation pens across the park. They took hold of the landscape, they proliferated, they thrived in the park, and spread throughout the region. Another 35 wolves were released in central Idaho at about the same time. Twenty years later roughly 500 wolves inhabit the Greater Yellowstone Ecosystem. Thirteen hundred more live elsewhere in the northern Rockies, and the gray wolf—that’s the common name, although individuals vary in color from pale brindle to black—has been removed from endangered species listing in Idaho and Montana. Wolves can now be legally hunted and trapped there. (The Wyoming situation is more complicated.) Today about a hundred wolves, constituting ten packs, live primarily within Yellowstone National Park, where Doug Smith, head of the Yellowstone Wolf Project, leads the effort to monitor, manage, and protect them.

On a cold December morning at an airport near Gardiner, Montana, just north of the park, I buckled into the back of a cherry-red Hughes 500D helicopter beside Smith for a glimpse of the project in action. Smith has worked with wolves for 37 years, with Yellowstone’s since their reintroduction, and has handled more than 500 individuals while they were tranquilized for collaring. He’s a tall man with a gray handlebar mustache and crow’s-feet that pinch around his smiling eyes. Seconds after we were securely aboard, the chopper levitated and then plunged toward the Yellowstone River under the touch of Jim Pope, a wildlife-capture pilot with an aerobatic flair. He leveled us off and then climbed again, sweeping south into the park, across the foothills, up over Sepulcher Mountain. Freezing wind ripped through our bubble as the treetops flashed by 200 feet below. Then we set down gently on a clear patch of snow behind Sepulcher. Pope’s crew—a pair of “muggers,” whose job was to fire a charge-propelled net, jump out, and tranquilize captured animals—had already immobilized two wolves.

Smith’s colleague Dan Stahler was also there, working with two other biologists on the drugged wolves. Kneeling in the snow, Stahler had almost finished fitting a collar on the bigger animal, a handsome black male, maybe three years old, with a small injury over his right eye. The other was a young female, light gray with a reddish brown head. Wearing purple medical exam gloves on a day that asked for warmer handwear, Stahler drew blood from the male’s right leg, then took a small tissue sample from the right ear for DNA work, while Smith adjusted a collar on the female. Smith measured the male: right front paw, body length, upper canine tooth—a little over an inch for the last. Upper canines are the teeth that show so menacingly when a wolf snarls at an enemy. But Smith called my attention to the carnassials. “Those are shearing teeth,” he said. “You don’t even want to get your fingers in there when they’re drugged,” although that was almost precisely what he was doing. Carnassials are their key teeth, he said—edgy and powerful, for slicing meat, cracking bone.

Smith and the team moved quickly. They lifted the male in a sling to weigh him: 55 kilograms, more than 120 pounds. They grabbed a fecal sample and injected a microchip between his shoulder blades. They weighed and measured the female. They took a rectal thermometer reading. Her body temperature had gone a little low, so they put her on a plastic sheet, wrapped her in jackets, and placed chemical hand warmers in her groin area while they finished other work. When they had their data, Smith invited me to kneel in the snow beside the big male and hold up his head for a photo. Cradling the animal gingerly, I noticed that his black fur was highlighted with grizzled and silvery tips. His tongue hung out, limp as a sock. He was groggy and helpless for now, but he was magnificent.

“Look at those eyes,” Smith said. They were wide open, blazing a coppery brown. “That’s wild,” he said. “This is what our world is trying to do away with. Right here, that look. We want to keep that look. That’s what Yellowstone Park is all about.”

Dazed and Confused

That’s what Yellowstone’s grizzlies are about too. Far from tame, as Horace Albright, that especially influential early park superintendent, wanted them, they are wild animals, powerful and well armed, jealous of their solitude, the females vehemently protective of their young. Lance Crosby’s death in August 2015 serves as only the most recent reminder of that. They’re also voracious—they’ve got to eat. Understanding the Yellowstone grizzly begins with considering its diet, and human flesh is an anomalous item, not even included with balsamroot and stink ant on the list of 266 items in the grizzlies’ diet.

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There were times in the 1970s and ’80s when the Greater Yellowstone Ecosystem held as few as perhaps 140 grizzlies, and the population seemed doomed, says Chris Servheen, a U.S. Fish and Wildlife Service official who coordinates grizzly recovery. Today 700 to 1,000 live there, including these two hulks tangling near the Firehole River. 


A camera trap at a watering hole caught grizzly and black bears bathing, splashing, and frolicking.

Kerry Gunther, who is Doug Smith’s counterpart as bear-management biologist for the park, spoke about this one afternoon as I sat with him in the backcountry, overlooking a site that doesn’t appear on the tourist maps: an odd, deep little spring that grizzlies sometimes use as a sort of bathtub. We had bushwhacked all morning to get there and eaten our lunches on a small knoll, talking of what Gunther had seen in 30 years of bear study and management in Yellowstone. He’s a quiet man, judicious in his statements, confident in his science, content to let others think what they will think, and dispassionate enough to view bitter disputes in which he and other managers are stuck between critics on both flanks as “interesting.”

In the 1980s, Gunther said, “every adult female bear seemed critical to the population. We were still at low population numbers.” Numbers were low because the grizzly population had crashed in the 1970s, after a change in management emphasis away from Albright’s yen for spectacle and toward greater attention to ecology. One signal event influencing that change was the Leopold Report of 1963, a landmark in the evolution of ideas about Yellowstone’s purposes and policies, which came from a review committee chaired by Aldo Leopold’s son Starker, a respected biologist in his own right. The Leopold Report, formally titled “Wildlife Management in the National Parks,” wasn’t the first voice to suggest an ecological approach to parks management—that idea went back to a foresighted animal ecologist named Charles C. Adams in the 1920s—but as a special advisory paper commissioned by the secretary of the interior, Stewart Udall, it carried considerable force. The report stated that conditions in each national park should be “maintained, or where necessary recreated,” so as to represent “a vignette of primitive America,” thereby affirming, but without untangling, the paradox of the cultivated wild. That and other factors—notably the public reaction to two grizzly-caused human fatalities, seemingly unrelated but shockingly coincidental, in a single night in Glacier National Park in August 1967—led to the closure of all Yellowstone dumps.

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Cutthroat trout, seen here spawning in the Gros Ventre River, are highly prized by anglers. Adapted to cold water, they’re threatened by a warming climate—and in Yellowstone Lake, by non-native lake trout. 


Shutting down that garbage buffet left the bears hungry, dazed by the sudden deprivation, confused, and reckless. They got into trouble, they suffered the consequences, their reproductive rate fell, and their population shrank drastically, to perhaps fewer than 140 throughout the ecosystem. During 1971 alone, more than 40 grizzlies were killed outside the park in various conflicts and mishaps, including bears that had been captured, marked, and released. The Yellowstone grizzly might have died out completely if the decline had continued for a decade.

But in 1975 the grizzly bear in the lower 48 was listed as threatened under the Endangered Species Act. Hunting of grizzlies ceased, at least as a legal sporting activity in the Greater Yellowstone Ecosystem, and the park adopted new policies to protect people from bears and vice versa. “We spent a lot of time managing individual bears, especially females, working really hard to try to keep them alive,” said Gunther, who came to Yellowstone in 1983. That meant forestalling bear-human conflict, by practical measures such as bear-proofing garbage cans and Dumpsters, patrolling campgrounds, educating visitors not to feed bears intentionally and not to allow them to pilfer human foods. The point was to keep humans and grizzlies at a respectful distance from each other and to encourage bear reliance on the natural foods they’d begun rediscovering after the closure of the dumps.

Many biologists suggest that it’s time to remove the Yellowstone grizzly from the list of threatened species. This is controversial. Everything about the grizzly is controversial. 

It worked. More females survived, they produced more cubs, “and the population has really turned around,” Gunther said. Grizzly numbers increased within the park, and their distributional range increased too, with bears now turning up in peripheral parts of the ecosystem where they hadn’t been seen in decades. Grizzly bears are hard to count, but the latest estimate from the Interagency Grizzly Bear Study Team, in just the core area of the ecosystem (they call it the Demographic Monitoring Area), and using an arcane mathematical model to extrapolate, puts that population at 717 bears. In the entire ecosystem, Gunther said, “I think we could easily be up around a thousand.” Based on such numbers, on the trend over recent decades, and on their belief that the Greater Yellowstone Ecosystem is now about as full of grizzly bears as it can be, many of the state and federal bear biologists suggest that it’s time to remove the Yellowstone grizzly from the list of threatened species.

This is controversial. Everything about the grizzly is controversial. Some conservationists outside the agency circle have challenged the population estimates, the positive prognosis, and the advisability of delisting. They’re concerned about the likely effects of renewed sport hunting and the long-term food security of the Yellowstone population.

Female Grizzlies with Cubs

Initial sighting

National Park Service

Greater Yellowstone

Ecosystem

1975–1984

Bozeman

MONTANA

Cody

IDAHO

WYOMING

Pinedale

2006–2015

Bozeman

MONTANA

Cody

IDAHO

WYOMING

Pinedale

40 mi

40 km

LAWSON PARKER; SHELLEY SPERRY; MARTIN GAMACHE AND LAUREN C. TIERNEY, NGM STAFF

SOURCE: INTERAGENCY GRIZZLY BEAR STUDY TEAM

Although that list of grizzly food items is extensive and diverse, just a few of the 266 deliver far more caloric intake than any others: cutthroat trout from Yellowstone Lake at spawning time, ungulate meat, whitebark pine nuts, and an unusual insect that aggregates in Yellowstone’s high country, the army cutworm moth (Euxoa auxiliaris). Each of those is an intricate story within the big saga.

The Omnivore's Dilemma

The cutthroat trout is the only trout native to Yellowstone waters. Rainbow trout, browns, brookies, and lake trout are all exotics, brought in since the park was established. Yellowstone Lake was a stronghold for the Yellowstone subspecies of cutthroat, the lake’s feeder streams offering shallow, well-oxygenated waters where it could spawn. Kerry Gunther’s first job at Yellowstone, as a fishery technician, involved monitoring cutthroat spawners in Clear Creek, one of the major lake tributaries, where he remembers a count of around 32,000 cutthroat spawners in one spring and early summer, all clambering into the shallows to mix their sperm and eggs in gravelly spawning beds. Grizzlies, black bears, coyotes, and other predators made good use of this easy food source. The first grizzly that Gunther ever saw was a big, dark-colored bear he encountered while snowshoeing in at the start of May 1983 to count spawning cutthroat. Being on snowshoes was no doubt a good reminder that you should never try to run from a grizzly. By 2006 the season’s count at Clear Creek had declined to 489 fish, less than a hundredth of the former number—therefore less than a hundredth the fat and protein available to bears fishing there. The decline continued, and spawning-fish counts in other tributaries around the lake have fallen almost to zero. Three factors, in deadly combination, account for this collapse: prolonged drought, especially affecting the tributaries; an ailment called whirling disease, caused by a parasite new to the system; and most important, the presence of lake trout, brought originally from the Midwest.

Lake trout arrived in Yellowstone Lake some decades ago, secretly introduced, presumably by a witless sportsman meaning to enhance the park fishery. They survived, they spawned, their population grew, but the alarm bell didn’t ring until 1994, when a fisherman on Yellowstone Lake caught a 17-inch lake trout. “Then everybody kind of had heart attacks,” said Pat Bigelow, a fishery biologist at Yellowstone. “Because it was pretty well known that the lake trout is a voracious predator.”

And a tough competitor. The big, adult lake trout in Yellowstone ate the smaller cutthroat trout and fingerlings, and before long the cutthroat population was a ghost of its former self. This was not just a trade of one trout kind for another, but a drastic shift in where the trout flesh resides. Whereas cutthroat trout hang shallow, often eating winged insects from the water’s surface or leeches and other small invertebrates in those shallows, lake trout tend to lurk in the deep, feeding on invertebrates also, or other fish, and usually doing their spawning down there, rather than running up into the tributaries. So they are far less available to bears, and their replacement of cutthroat trout represents a severe loss for those grizzlies that once feasted at spawning streams.

Bigelow came to Yellowstone from Vermont in 1979, as a member of the Young Adult Conservation Corps, and she remembers seeing fishermen on Yellowstone Lake catch and release 50 cutthroat in a day. That doesn’t happen anymore. The catch for cutthroat is down, and if you fish there today and catch a lake trout, park regulations require that you kill it.

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A magpie mobs a group of river otters on the Snake River, Grand Teton National Park. Magpies follow otters in winter, attempting to scavenge leftover bits of fish.


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A weasel blends into snow in Grand Teton. In spring it will molt and turn light brown. Cutthroat trout, seen here spawning in the Gros Ventre River, are highly prized by anglers. Adapted to cold water, they’re threatened by a warming climate—and in Yellowstone Lake, by non-native lake trout.


But sportsmen will never solve this problem. Bigelow showed me, during a long, fishy morning aboard a large, steel boat on Yellowstone Lake, how the park is trying to cope with it wholesale: by contracting a company from Baileys Harbor, Wisconsin, on Lake Michigan, to bring Great Lakes–style commercial fishing methods to the task of exterminating lake trout. For most of five hours I stood beside her, wearing orange vinyl overalls, rubber boots, and a life jacket, like everyone else. The gill nets coming up held large, greenish gray fish—four pounds, five pounds, two feet long—that could be considered beautiful animals if only they weren’t exotics causing such harm to an ecosystem. I watched Bigelow and the boat crewmen wrestle these fish from the nets, measure them, count them, then slit them open with sharp knives, check for eggs, puncture the air bladders, toss them gasping and dying into plastic tubs, and eventually dump them all back into the lake, allowing the nutrients to remain in the system. Our boat had killed and dumped 238 fish by lunchtime, amounting to half a ton of lake trout. Meanwhile three other boats were inflicting similar carnage. The work was gruesome and heartless—and justified, for the sake of not just the Yellowstone cutthroat but also the grizzly.

These commercial boats have been working a long season each summer since 2011, and the cutthroat have begun showing modest signs of recovery. But the lake trout may never be extirpated, and so the suppression effort can probably never end. “If it fails,” Bigelow said, “it’ll be because we didn’t try hard enough.”

The loss of whitebark pine nuts from the grizzly bear menu is a more complicated concern, lying further beyond human fixing. These fat-rich little morsels—they’re called nuts but are really pine seeds—come to ripeness within cones on the trees, which inhabit the Yellowstone ecosystem only at high elevations, above 8,500 feet. Whitebark pines grow slowly, reaching cone-bearing maturity after 50 years. Grizzly bears get the nuts mainly by raiding cone middens of red squirrels, which store them for winter. Clark’s nutcrackers, gray-and-black birds in the crow family, also harvest the nuts and hoard them buried in little caches of several seeds each, and most new whitebark pines grow from nutcracker caches that have gone unrecovered by the birds.

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Notoriously elusive, cougars vary their range in response to their prey, mostly elk and deer. In winter they favor the shallow snow in the northern reaches of Yellowstone. This cougar was caught on the prowl by a camera trap set behind an elk rack on a cliff. 

The greatest enemy of the whitebark pine is the mountain pine beetle, a tiny bullet-shaped insect that burrows tunnels in a tree’s living tissue, which can interrupt nutrient flow and kill the tree. Whitebark forests have always suffered episodic attacks by mountain pine beetles, but in recent years the beetle kill has gotten much worse, probably because of climate change. Severely cold weather, especially deep cold snaps that occur early in winter or late in spring, can knock down the beetle population. But that sort of weather is now rare, and since 2003 a vast beetle outbreak in the Yellowstone ecosystem has resulted in unprecedented killing of whitebark pines.

“The whole defensive strategy of the whitebark is escape,” said Jesse Logan, a forest entomologist, as we stood amid a grove of whitebarks in the Absaroka Range. “It’s a hell of a survivor. But it’s not much of a competitor.” At high elevations, in cold and harsh conditions, it largely escapes competition from other conifers—ponderosa pine, lodgepole, Douglas fir. But it doesn’t escape the beetle, not anymore.

Logan’s aerial surveys, done with William Macfarlane, a colleague from Utah State University, suggest that almost half the whitebark distribution in the Greater Yellowstone Ecosystem has now suffered severe mortality from the mountain pine beetle, and 82 percent has suffered at least moderate die-offs. Logan pulled some bark off a dead tree to show me the beetles’ tunnels, vertical and crisscrossing, like a subway map of New York City. “My sense is that the loss of this food resource is really important to grizzlies,” he said. He’s not a bear biologist, and others disagree, but the issue is serious.

Food on the Wing

Grizzly bears get more energy ­—kilocalories per gram—from army cutworm moths than from any other food. The moths appear only in summer and early fall, when they fatten on nectar

from wildflowers.

7.9

kcal/

gram

7.3

5.2

3.9

Mule deer and white-tailed deer

3.2

Army cutworm moths

Whitebark pine nuts

Cutthroat trout

Huckleberries

Dying Pines

 

Mountain pine beetles are killing whitebark pine trees across the Greater Yellowstone Ecosystem. Warmer temperatures have allowed the beetles to invade higher elevations, where the iconic pines grow.

Whitebark mortality

Trace

5%

Severe

46%

Low

13%

36%

Moderate

Based on a 2009 tree-mortality survey

LAWSON PARKER; SHELLEY SPERRY; MARTIN GAMACHE, NGM STAFF

SOURCES: KERRY GUNTHER, NPS; WILLIAM W. MACFARLANE, UTAH STATE UNIVERSITY

Army cutworm moths are more unexpected, more fortuitous in the grizzly bear’s diet, because unlike whitebark nuts and cutthroat trout, they come from elsewhere. These little gray creatures migrate hundreds of miles in early summer from lowland farming areas—on the Great Plains and in the intermountain West, where in the larval stage they’re crop pests—to high elevations in the Absarokas and elsewhere. They spend the hot days hunkering in cool, moist recesses amid scree slopes (fields of broken, tumbled rocks) above 9,000 feet, and at night they fly out to drink nectar from wildflowers in alpine meadows. Metabolizing the nectar, they lay on rich stores of fat, enough to see them through their arduous return migration in the fall back to crop fields in Kansas, Nebraska, or wherever. A moth that arrives in the mountains in late June, having 40 percent body fat or less, can increase to 65 percent fat or possibly more by the end of the summer. Lapping up such creatures from amid the scree, for a grizzly bear, is like eating pill capsules filled with olive oil by the handful. A grizzly can consume about 40,000 moths in a day, representing about 20,000 calories, which makes the moths ideal food during the hyperphagia period of the bear’s year, when it’s fattening itself for winter hibernation. At that rate a grizzly feeding for 30 days on army cutworm moths can satisfy almost half its yearly energy needs.

One of those moth sites lies on the northwest face of a mountain high above a beautiful little basin near the headwaters of the North Fork of the Shoshone River. On a cool day in late August, Mark Bruscino, formerly chief of large-carnivore management for the Wyoming Game and Fish Department, led a small group of us to the site, seven hours by horse into the North Absaroka Wilderness. Our packtrain had been assembled by Lee Livingston, an outfitter and county commissioner out of Cody, who rode caboose. We made camp in a glade, drank some whiskey, ate well, and awoke the next morning to find that a small, late summer storm had covered the higher slopes with a thin blanket of snow. We stood at spotting scopes all morning, watching seven grizzlies work their way across the whiteness of a scree slope far above. The bears were burly and dark, their paths turning scree brown against the white as each bear tossed aside 40-pound rocks, digging down, slurping moths, moving slowly on. For a while I watched one grizzly, his huge butt protruding in the air as he dug, rummaged, snarfed, and then occasionally lifted his head, as though to take a breath and swallow. Not far from him, a female and two cubs also fed, tolerating the male at what would be unacceptably close proximity (because male grizzlies sometimes kill cubs and eat them) under other circumstances. But they were all preoccupied now, gobbling moths, acquiring fat.

So far this year, Bruscino told me, his old colleagues had counted about 200 individual grizzlies working dozens of moth sites. That’s about a fifth or a quarter of the ecosystem’s grizzly population, he reckoned, all feeding on moths while they’re available. His arithmetic assumed, as did Gunther’s, about a thousand grizzly bears—a huge rise since the nadir of the 1970s. “To me,” he said, “this is one of the greatest wildlife-restoration stories ever.”

The grizzly still faces threats, Bruscino noted, but the worst is not the loss of whitebark pines nor of cutthroat trout. It’s not that the moths might disappear or become poisonous if farmers in Kansas decide to use more pesticides. “The biggest long-term threat to this bear population is private-lands development,” he said.

Rivers of Elk

A month earlier I had ridden over a pass elsewhere in the Absarokas, southwest of Cody, to meet a young ecologist named Arthur Middleton, who was hard at work in the remote Thorofare area outside the park’s southern boundary, tracing the intricate migrations of Yellowstone elk. My guide this time was Wes Livingston, Lee’s brother, another backcountry horseman who grew up in these mountains and knew every creek and trail. Livingston wore a camo T-shirt, a droopy mustache, an elk-tooth necklace, a weathered felt hat that didn’t even bother to look cowboy, and a titanium .44 Magnum on his belt, in case he needed to shoot an injured horse or mule. He led a string of five pack mules and an extra horse, as I followed him up a long switchback trail toward Deer Creek Pass.

It was late July, but nearing the top, we faced a dicey stretch where the narrow trail still lay buried beneath a drift of old snow. Off the left side was a steep plunge toward Deer Creek far below. Livingston stampeded his animals across, their hooves postholing into the snow, their momentum carrying them through. As I tried to follow, my horse—a steady buckskin named Jimbo—balked, floundered, and got himself turned. “Get off!” Livingston hollered, then coached me to grab Jimbo’s lead rope and walk him back onto the dirt to regain his footing. I followed instructions, and eventually we all got across.

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On their first migration to their summer range in southeastern Yellowstone, three-week-old calves of the Cody elk herd follow their mothers up a 4,600-foot slope. A few hours earlier they swam the swollen South Fork of the Shoshone River.

At the top of the pass we noticed a scoop shovel, stashed there for the use of snowbound hunters. Then the trail tipped down gently into a wide, meadowy valley on the Thorofare side, and Livingston laconically declared, out loud but to himself, “Didn’t roll any donkeys down the mountain.” I wasn’t sure whether “any donkeys” referred to the mules, the horses, or me.

We joined Middleton at his camp near the mouth of Open Creek, from which he would range up into the high meadows in search of summering elk. The following morning, over a campfire breakfast, he talked of elk dynamics. The northern herd in Yellowstone Park is famous, he said, for its fluctuations between excessive abundance and relative scarcity, due partly to natural factors, including now again wolf predation, and increased bear predation, and partly to direct human actions. That’s the herd most familiar to visitors, thanks to its conspicuousness along roadsides from the Hayden Valley to the grassy lawns around Yellowstone’s headquarters buildings at Mammoth Hot Springs. The other herds probably haven’t experienced such drastic fluctuations, for reasons that vary by herd and might include open terrain, long sight lines against predators, strong winds that blow away snow, and the animosity of private landowners toward wolves.

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Members of the Cody herd traverse Thorofare Plateau—the most remote area in the lower 48—just outside the southeast corner of Yellowstone. The elk bands graze there until early autumn, when snow pushes them out of the mountains. 

There was history behind this. The massive slaughter in the late 19th century took elk numbers way down, but then came an elk boom that increased under Horace Albright’s protection, and then a policy reversal after elk seemed too abundant, especially on the northern range of the park, resulting in an active elk-reduction program that lasted from 1934 to 1967. Whipsaw changes. During that long elk-reduction regime, park rangers shot 13,753 elk from the northern herd, private hunters killed 41,400 when the animals migrated out of the park, and almost 7,000 were trapped and shipped away to forests and zoos elsewhere. In the late 1960s the park superintendent and his chief biologist, influenced by the Leopold Report and some fashionable new thinking in ecology, embraced a policy called natural regulation. But what were the limits of “natural” in the service of “regulation”? Was it more natural to let elk starve than to hunt them? Was it more natural to haze bison back into Yellowstone with helicopters, trucks, and rangers on horseback than to ship them to slaughter so that the meat could go to Native American tribes? Hard to say. That fancy phrase “natural regulation” served to codify in two words—but not solve—the paradox of the cultivated wild.

As for wolves, reintroducing them was a bold act of management that did restore some “natural” conditions. But how far do those conditions ramify?

Attitudes toward the wolf are more bitterly polarized and complex than those around any other creature in Yellowstone. Beyond the wolf-haters-versus-wolf-lovers tussle, scientists disagree about how and to what degree wolves are reshaping the Yellowstone ecosystem. Do they reduce reproductive success among elk simply by creating a landscape of fear, wherein the great bulls and cows are too nervous to eat and procreate? Have wolves killed enough elk to curtail elk browsing on aspen and willow shoots? Has that reduced browsing allowed aspen and willow stands in Yellowstone to recover and renew themselves for the first time in decades? Has such aspen and willow recovery enabled the return of beavers and songbirds? Or is reality a little more intricate? Some scientists and wolf advocates tell this story in happy, simplistic terms. “But it’s an unproven theory that gets undue attention,” Middleton said, “in the quest to have wolves shine rainbows out of their asses.”

WINTER

National Park Service

Elk range

MONTANA

IDAHO

WYOMING

SUMMER

Elk range

MONTANA

IDAHO

WYOMING

40 mi

40 km

LAWSON PARKER; SHELLEY SPERRY; MARTIN GAMACHE AND LAUREN C. TIERNEY, NGM STAFF

SOURCES: ARTHUR MIDDLETON, YALE UNIVERSITY

Middleton is an improbable fit for the role of Wyoming elk maven: a South Carolina kid, a graduate of the Yale School of Forestry and Environmental Studies, who came west nine years ago, having landed work on a study of elk-wolf interactions commissioned by Wyoming Game and Fish. After arriving in Cody to meet his new collaborator, he admitted that he’d never seen a wolf or an elk. But he learned fast, and he loved the mountains. He put GPS collars on elk, clarifying poorly understood patterns in their movements between summer and winter ranges. He collated similar data from other researchers and made eye-opening digital maps. Look where these animals go. “Most of Yellowstone’s elk,” he said later, “are not in Yellowstone for most of the year.” They’re off the plateau, down on winter range, where the snow isn’t so deep and the temperatures aren’t so brutal, largely on private ranches. By this time Middleton had a Ph.D. from the University of Wyoming and a postdoc position back at Yale. His hair was long, his speech was slow and considered, his brow scrinched when he pondered something carefully. Within a short time at least one Cody-based game warden began referring to him as “the elk hippie.”

Middleton’s mapping of the elk data showed at least nine distinct migratory herds, each moving seasonally in a different direction. Many of Grand Teton’s elk winter in the National Elk Refuge, just north of Jackson, Wyoming. Thousands from the other herds move down onto ranches. Along the South Fork of the Shoshone River and in the upper Greybull River Basin, southeast of Cody, many of them winter on historic spreads such as the Pitchfork Ranch and the T E Ranch. From there, in summer, they migrate 50 miles across two difficult passes to reach the verdant highlands above Thorofare Creek, just outside Yellowstone’s southeast corner. That’s why Middleton was here: to find them on their summer range.

Several days into our Thorofare trip we rode up out of the valley and camped high, at about 9,200 feet, atop the Thorofare Plateau. The next morning Middleton and I went higher, picking our way through a jackstraw mess of downed timber from the great fires of 1988, our horses stepping carefully over the logs, then onto the easier footing of a meadow, amid the short grasses, the Indian paintbrush, the purple asters. Cresting a ridge, we saw about 150 elk—bulls and cows, some calves—grazing and resting on a green slope in the near distance. From the Cody herd, Middleton said. Part of what he wanted to do here, he explained, was gauge the cow-calf ratio. If 80 percent of the cows had calves in spring, and only 40 percent did now, where did those other calves go? How many had been eaten by grizzlies, how many by wolves?

And where would they go in winter if the Pitchfork and the T E and the other big ranches wouldn’t tolerate them? When the alpine grasses go brown, when the frosts hit, when the snow flies, the elk have got to come down from these highlands and all the others to find more clement conditions. But those migrations are in some danger of being choked off—as Mark Bruscino too had warned me—by private land development that turns winter range into vacation homes for the wealthy, sprawling suburbs for the middle class, and commercial areas that serve all sectors of the Greater Yellowstone Ecosystem’s growing human population. Many people understand this, at least dimly, but want to own a piece of the scenery anyway. Wes Livingston made the point pungently, as we sat drinking coffee: “It’s called the last-son-of-a-bitch clause. ‘Let me in, and then close the gate.’ ” Blocking the migration corridors, by settlement on lands just outside Yellowstone and Grand Teton, will interrupt an essential flow of ungulates and all the values—nutritional, ecological, aesthetic, financial—they carry.

It’s the same basic truth that Gen. Philip Sheridan recognized back in 1882, further illuminated by research such as Middleton’s: Yellowstone’s elk need the Greater Yellowstone Ecosystem, all of it, and the ecosystem needs Yellowstone’s elk.

Livingston had a piece of advice, he told me, for the righteous, out-of-state, vacation-home-owning greenies he sometimes met. If you really want to help Yellowstone wildlife, he would say, “burn your house down and go back to California.”

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A moose fords Buffalo Fork River near Grand Teton. An increase in natural wildfires and the return of wolves and grizzlies to the region have dramatically reduced the moose population. Climate change may be a contributing factor as well. 

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