by Sam Kean
KIM TODD
The Island Wolves
from Orion
In the Bone Garden, moose antlers sprout like pale stalks of mutant corn. Skulls, lined up one behind the other, bear tags that sketch moose lives: “2 yrs. old starved, winter ’96” and “Died 1989. Wolves dug through 2 ft. of snow to feed on it in 1990.” The curious visitor to this small plot on Lake Superior’s Moskey Basin in Isle Royale National Park can also marvel at thematic displays: worn skulls by a sign declaring “The Odd Fellows corner—old bulls no longer reproducing, antlers in decline” and shelves of the skulls and antlers of dead young males labeled “Darwin Award Winners.”
No wolf bones lie here—they have been sent to a lab at Michigan Technological University with thousands of moose metatarsals—but the Bone Garden’s skulls and antlers are a library of wolf sagas written in gnawed jawbone. Isle Royale, an isolated wilderness of boreal forest and sheltered swamp surrounded by a rocky shoreline and dotted with plentiful loons, is the site of the longest-running study of predator-prey dynamics in history, spanning almost six decades. To ecologists, these bones tell some of the most famous animal stories in the world, framing ideas about what it means to eat and be eaten, and how the battle to survive shapes the land.
But now, it appears the stories have been misinterpreted.
“I was dead wrong,” says Rolf Peterson, who has been studying wolves and moose on Isle Royale since 1970. Peterson, dressed in a plaid shirt and down jacket patched with duct tape, gray beard still streaked with a hint of red, gives me the garden tour, pointing out two skulls locked together in what must have been a fight to the death. His speech is slow and thoughtful, marked by a rueful chuckle.
For years, Isle Royale National Park has been considered the perfect natural lab: a closed system with one dominant predator, the wolf, relying heavily on one kind of prey, the moose. A 45-mile-long island in one of the world’s largest lakes, Isle Royale is defined by solitude. Miles from the mainland, in the summer, the park can only be reached by seaplane, private boat, or a half-day ferry ride from either Michigan or Minnesota; in winter, the park is closed, abandoned to deep snows and wildlife. Though few in numbers, the wolves marooned in the park thrived for years, seemingly free of the deformities and stillbirths that plague populations where close relatives breed. Recording wolf and moose numbers and documenting hunting and fleeing, biologists charted two species intimately intertwined. But recent revelations resulting from DNA tests took everyone by surprise.
“You think if you watch a place for a long time, you’ll have a deeper understanding,” says John Vucetich, lead scientist of the wolf-moose study. But the new information upended expectations. “It’s not as though it was an accumulation of knowledge; it was a full-scale reversal of what we know.”
For centuries on Isle Royale, there were no wolves, just caribou lurking in the balsam fir and lynx chasing snowshoe hares over the stone outcroppings, until hunters and trappers cleared them out. Moose arrived on the island by the early 1900s, probably by swimming, and lived there for about 50 years without any predators. Then the wolf rumors started, spurred by possible signs: an outsized paw print on a beaver dam. Scat laced with moose hair.
In the early 1950s, Lee Smits, a newspaperman and conservationist, saw Isle Royale as the perfect spot for a wolf refuge, a place the predator could be safe from the poison, guns, and traps that killed off most of its kind in the Lower 48. There were no ranchers to anger or sheep to harass. Maybe wolves would find their way to the island themselves. Maybe they already had, Smits thought. But he wanted to be sure. He asked trappers on Michigan’s mainland to keep an eye out for pups that could be introduced to Isle Royale to start a pack. When they didn’t find any, he turned to the Detroit Zoo.
Lady, Queenie, Adolph—the chosen wolves had names. The fourth was Big Jim, a bulky male descended from Saskatchewan stock and bottle raised by Smits and his wife. Big Jim learned to retrieve ducks by playing with their water spaniel. Not surprisingly, when brought to the island in August 1952, the zoo wolves didn’t know how to behave. Instead of chasing down moose, they chewed up fishing nets, raided laundry lines, and hung out near the Rock Harbor Lodge. As a New York Times headline summed it up, “The Wild Calls in Vain to Four Urbane Wolves.”
Rangers hauled them to a more desolate spot, but they came back to the lodge, startling tourists. By then, the rangers were fed up. They shot Adolph. And then Queenie. They captured Lady and took her back to the zoo. Big Jim escaped. He turned up here and there over the years. In 1957, a park service biologist reported a wolf trailing him like a wary dog. But no one much cared, because before long there was solid evidence of other wolves, too, wild ones. A year later, Durward Allen, a professor at Purdue University, and his graduate student L. David Mech launched a study of these wolves, the moose, and their entanglement.
The scientists’ conclusions quickly found their way into textbooks about predators and prey. Pick one up, even today, and you will likely find pictures from Isle Royale: wolves like black bullets tearing through snow, biting at the heels of a calf stumbling in the deep drifts. The spray of blood and exposed spine on a creek bank. A whole pack, photographed from above, spreading out over the frozen lake, scribbles of tracks and shadow, like graphs on white paper.
In these textbooks you will also find actual graphs—all this behavior abstracted, slobbering tongues and flicking whiskers and clumps of hair smoothed away—because they illustrate the lesson so neatly. Allen and Mech’s research fit perfectly into the Lotka-Volterra predator-prey model. Developed in the 1920s, the model is a set of differential equations that show the predictable way the fates of species are tied together. As the prey population grows, the predators, finding more food, also flourish. As young are eaten and adults harried, the prey population falls. The predator population then also falls, as their food grows scarce. The equations produce graceful waves, one trailing the other—a field mouse leaping, a fox leaping after.
In his book Sociobiology, Edward O. Wilson described Isle Royale and these early studies as “a simple and instructive example of the balance between predator and prey.” He highlighted the benefits of this balance for the prey, often pitied as victims:
The moose, by unwillingly supplying the wolves with one of their members about every three days, have stabilized their own population . . . As a curious side effect, the moose herd is kept in good physical condition, since the wolves catch mostly the very young, the old, and the sickly individuals. And, finally, because the moose population is not permitted to increase to excessive levels, the vegetation on which they feed remains in healthy condition.
In Wilson’s description, the orderly cycles gestured at an irresistible, uplifting tale. The Isle Royale study has the same appeal as a Jack London novel—harsh beauty, high drama, and, importantly, an explanation for the violence of the natural world.
As a high school student in Minneapolis, Rolf Peterson read about Durward Allen’s work in the Star Tribune and plastered newspaper photos of Isle Royale foxes on his wall. A 1963 National Geographic article, “Wolves Versus Moose on Isle Royale,” further whet his appetite. It showed a golden-eyed wolf staring down the research plane used for winter counts and a pack swarming at a faltering cow moose. It described wolves howling, a sound few in the continental United States had ever heard. As a college senior in 1969, Peterson wrote to Allen at Purdue and asked to be part of the study. Allen said yes.
Peterson tells me this story at the kitchen table of the weathered Bangsund log cabin that, for decades, has served as the base of operations for the Isle Royale study. The cabin has bright red trim and a sign on the door that reads, THIS IS OLD GLASS. PLEASE DO NOT LET THE DOOR SLAM IN THE WIND. Inside is a small wood stove. Island maps cover the wall, the table, and the low, sloping ceiling. The decor consists of a howling wolf in stained glass, a hanging moose skull, and beaver skulls on the windowsill. The overall aesthetic is that of a field-research station crossed with Little House in the Big W
oods. At night the cabin glows with the light of solar-powered paper lanterns.
Peterson traces wolf-pack movements on the map on the table, takes out the 1963 National Geographic, and reads lines near the end of the article about the island: “Our studies thus far indicate that the moose and wolf populations on Isle Royale have struck a reasonably good balance.” The wolf numbers had remained stable, at around 20 or so, and the moose numbers, as best as they could count them, seemed to be holding steady too. “The notion of balance was firmly ingrained in everything,” Peterson says. When Peterson joined the study, it had already been running for 12 years, and the chief ranger said to him, “You’re in the 12th year of a 10-year study. What are you going to do?”
But Allen told Peterson, “Just watch, something will happen.” And it did.
During Peterson’s first summer season, everything began to break loose. After a series of harsh winters, wolf numbers soared, going up to 50 in 5 packs at one point. Behavior changed, with wolves chasing moose off cliffs and eating just the organ meat before killing again. Moose numbers plummeted, then wolf numbers plummeted. Then wolf numbers rose again. What was causing such dramatic shifts?
As the scientists plotted the data, tidy Lotka-Volterra waves vanished, replaced by something else. “It’s like a big historical novel. Every 5-year period looks completely unlike any of the previous 5-year periods, and the dynamics are driven by external events that we cannot imagine, let alone predict,” Peterson says.
Though the biologists flew over in helicopters, recording all they could see, unseen forces governed the island. In 1997, one of the coldest winters of the century, the lake froze. Blizzards battered the Lake Superior shore, and a hulking wolf, who would grow silver as he aged, struck out from Ontario in the direction of Isle Royale.
He found an island reeling. In 1981, an infected dog from Chicago, brought in illegally on a private boat, had carried canine parvovirus to the island. No pups survived that year, and the wolves had not entirely bounced back. Two years before the lone wolf’s arrival, the moose, up to almost 2,500 head, had chewed balsam fir to nubs and starved, crashing down to about 500 individuals. Wolves suffered as a result: old ones died, pups died, and those who scraped through did so on empty stomachs. Hungry survivors gnawed the hide of a moose that had been dead for a full year.
Unconcerned by the bleak conditions, the newcomer took over. With him at the head, the Middle Pack, one of three packs on the island at the time, aggressively expanded beyond its moose-poor territory, claiming richer areas such as Chippewa Harbor. The new wolf raised six pups in 1998 and three the next year. The island’s wolf population surged. Noting a clear new pack leader with increasingly pale fur, and not knowing he came from the mainland—not knowing any wolves still came over from the mainland—the biologists dubbed him Old Gray Guy.
The idea of a balance in nature is at least as old as Herodotus, the Greek historian, who tried to understand why prey animals weren’t entirely consumed. Investigating, he gathered reports from the Middle East: “Of a truth, Divine Providence does appear to be, as indeed one might expect beforehand, a wise contriver. For timid animals which are a prey to others are all made to produce young abundantly, that so the species may not be entirely eaten up and lost; while savage and noxious creatures are made very unfruitful.” For many years, this sense of balance was the hinge between religion and biology. William Derham wrote in his 1713 book Physico-theology: or, A Demonstration of the Being and Attributes of God, from His Works of Creation that divine management can be seen in the “Adjustment of the Quantity of Food to the Number of Devourers, so that there is not too much, so as to rot, and annoy the World.” Though underneath the cheerful accounting lay the niggling question: why was this violent, unending cycle part of the divine plan?
In the late nineteenth and early twentieth centuries, some writers came up with an answer: it wasn’t. Plains were empty of bison, woods had only a few deer. Conservationists predicted that predators would do what Herodotus thought they couldn’t: eat prey into extinction. Teddy Roosevelt, in his 1893 book The Wilderness Hunter, wrote, “The wolf is the arch type of ravin, the beast of waste and desolation.” Ravin connotes robbery, greed, and plunder. William T. Hornaday, in Our Vanishing Wildlife, constantly referred to wolves as cruel, and said insatiable human hunters have “the gray-wolf quality of mercy”—by which he meant none. This language fed the vicious predator-extermination campaigns.
Against this wave of righteousness, author Ernest Thompson Seton built a seawall of romance. In his most famous story, “Lobo, the King of Currumpaw,” the noble outlaw Lobo, who is the leader of a wolf pack, is done in by his love for the beautiful but ditzy Blanca. The narrator, a wolf hunter who traps Lobo at last, finds himself moved to mercy: “Yet before the light had died from his fierce eyes, I cried, ‘Stay, we will not kill him; let us take him alive to the camp.’” Lobo dies anyway.
Seton’s books are the definition of charm. Ink sketches adorn the margins: a nest at the top of a tree that runs the whole length of the page, musical notes showing the various caws of the crow, a fox tugging a chain to release her son, a jotting of poison sumac, partridge tracks wandering over the paper field. The title type is like something burned into wood over a cabin door.
Seton’s prose is as idiosyncratic as his books’ design. In Wild Animals I Have Known, Seton lays out his methodology for what might be a book of natural history or a collection of short stories or a series of animal fables for children: “I believe that natural history has lost much by the vague general treatment that is so common. What satisfaction would be derived from a ten-page sketch of the habits and customs of Man? How much more profitable it would be to devote that space to the life of some one great man. This is the principle I have endeavored to apply to my animals.”
Seton’s weird notions about how to write about grizzlies and rabbits faded from popularity. But Lobo lived on in what is probably the most significant story of the American conservation movement, 1949’s “Thinking Like a Mountain” by Aldo Leopold. The dying wolf at the end of Leopold’s essay is an echo of Lobo: “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.” What she and the mountain know is that wolves keep the deer in check, deer that would otherwise destroy the mountain. The 1963 National Geographic Isle Royale article used Seton’s character as a stand-in for all of his kind: “The truth is that Lobo is gone from nearly all his old haunts.” For a long time, when someone said wolf, Lobo came to mind.
That is until the Isle Royale wolves replaced him in the American imagination, swapping out one wolf tale for another. Lobo is the story of an individual, heroic and tragically flawed. The Isle Royale wolves have long been interpreted as characters in a narrative about how a good system works. No less noble than Lobo in their way, they restore the balance of nature. In this update of the ancient idea, though, balance results from natural selection rather than a divine manager.
If Isle Royale is the textbook example of the predator-prey relationship, Yellowstone is the Imax movie. Only a few years after wolves were reintroduced there in 1995, they were credited with the park’s transformation. They ate elk. This reduced elk browsing, allowing aspen and willow to shoot to heights they hadn’t reached in decades. Healthy groves of aspen and willow, in turn, sheltered beavers and birds. This chain of effects is called a trophic cascade, where a predator sends ripples throughout the food web. It is a similar idea to that of a keystone species, where, for example, a sea star on the Washington coast, once removed, causes mussels to flourish and limpets to decline. According to this view, some species have an outsized effect on the entire landscape, shaping the ecosystem. But brush the soil off these notions and “balance of nature” appears as their bedrock: “Wolves keep Yellowstone in balance” declares a blogger on the website Canis Lupus 101.
Yet as Pe
terson and his colleagues counted wolves, counted moose, and tracked Old Gray Guy and his offspring through meadows and bogs, balance on Isle Royale proved increasingly elusive.
In February 2000, Rolf Peterson and his pilot saw a wolf cowering on a rock offshore as their plane skirted the coast. The Middle Pack waited on the bank to finish her off. Led by Old Gray Guy, the pack had become a powerhouse, taking over 75 percent of the island and killing a stray male from the East Pack two days before.
As Peterson watched, the wolves surged into the water, snarling and biting at the wolf on the rock, then retreated. After weathering a dozen attacks, the lone wolf jumped into the icy lake and swam to another rock, then another. The pack followed on land, rushing through the waves to tear at her whenever she paused. A photo from above shows the pack on a submerged stone, arrayed like a sea star around a point—the wolf in the center, downed and invisible.
Peterson, talking into his tape recorder, said three times, “I think she’s dead now.” But she kept getting back up. Finally, after making it to shore only to be attacked again, she seemed definitively gone.
The men eventually flew to Windigo for a body bag and to refuel. When they got back, a male who had been far behind his pack mates approached the carcass. And then, as Peterson later wrote in his report, “the lone female raised her head!” (See The Ecological Studies of the Wolves of Isle Royale, 1999–2000.) The next day, both wolves were gone, leaving behind bloody indents in the snow where the female had slept.
Several days later, Peterson found the pair. The female was standing up and the male was licking her neck. Every now and then he’d dig in the snow to imitate caching food—courting—and she’d growl, and he’d go back to licking her neck. The scientists dubbed her the Cinderella wolf, but Cinderella doesn’t seem right. Maybe the second wolf staged a rescue, but invoking the fairy tale obscures the first wolf’s own swimming and fighting and snarling determination to live. There was no fairy godmother or party dress. A better name for her is Ferocious Warrior. The male wolf—he can be Prince Charming.