Where the Wild Things Were

by William Stolzenburg

  Alfred Russel Wallace, Darwin’s codiscoverer of evolution by means of common descent, had too marveled at the great bestiary whose remains had been unearthed in the Pleistocene beds not only of North America but around the globe. “We live in a zoologically impoverished world, from which all the hugest, and fiercest, and strangest forms have recently disappeared,” he wrote.

  Surely, thought Wallace, in line with many of his contemporaries, the Pleistocene ice must have been the dagger that killed the megafauna. Yet even as he argued the case for climate’s role, Wallace was subconsciously implicating a second party. “This is certainly not a great while ago, geologically; and it is almost certain that this great organic revolution, implying physical changes of such vast proportions … has taken place since man lived on the earth.”

  Since man lived on the earth. The point struck Martin a hammer blow. The glaciers had waxed and waned, climates had blown hot and cold with the wild swings of the Pleistocene, but the first arrival of humans on the continent had only happened once, and that, it appeared, had coincided all too suspiciously with the disappearance of the megafauna.

  Martin’s suspicions had come at an opportune time. The field of paleoecology had recently entered the revolution of radiocarbon dating, a technological timepiece with which one could precisely age life-forms long dead by measuring an odd form of carbon in their bones. Carbon 14 is a rare and radioactive molecule, a trillion times less common than its ubiquitous cousin carbon 12, but nonetheless taken up in measurable quantities in the tissue of all living matter. Carbon 14 is an unstable molecule, steadily leaking neutrons like grains of sand from an hourglass. When life stops, carbon 14 starts vacating its host, dwindling by half every 5,370 years. With a good sample, geochemists could date the death, to within a few centuries, of an animal that had died up to 40,000 years ago.

  What the radiocarbon had begun to reveal was a North American menagerie of some forty species of mammal, all weighing more than one hundred pounds, coming to an abrupt end. All but fourteen had disappeared, and most of the casualties indeed clustered around the arrival of humans.

  To those of the climatic persuasions, it was telling that 13,000 years ago—the cliff in time over which most of the megafauna of North America tumbled—the land was coming out of the latest glacial cycle, warming and drying and generally rearranging the continent’s communities of plants. But to those leaning toward man as the smoking gun, it was more telling that most of these animals had already breezed through twenty-two such glacial cycles of the Pleistocene, some of them more severe than the latest.

  Whatever or whomever the phantom killer was, it visited South America shortly after cleaning out North America, removing 80 percent of that continent’s large mammals. And strangely enough, the same sort of blight had apparently blitzed Australia some 40,000 years ahead of the American massacre, taking the island continent’s giant marsupial mammals, its giant flightless birds, and a lizard sixteen feet long. It did so too on the heels of human arrival, with no glaciers in sight.

  In the Americas, the final years of the megafauna coincided with the first appearance of the Clovis culture and their exquisite spear points. Flaked from chert and flint and quartz, and sharp as broken glass, they turned up in brilliance and abundance in sites across the country. Some of them were recovered from between the ribs of fossil mammoths. The Clovis people, carrying the name of the dusty little town on the plains of eastern New Mexico where their artistic weapons were first uncovered, began showing up in North America around 13,400 years ago. They were the descendants of Siberian mammoth hunters who, during a period of low water, had walked across the Bering land bridge to Alaska. Southward they wandered, through an ice-free corridor, into a land of giant beasts that had never seen such odd creatures as these shifty bands of two-legged waifs wielding fire and hurling pointed sticks. To Martin, it was tantamount to a superpredator entering Eden. Spreading at a reasonable pace of 2 to 4 percent per year, cleaning out the naïve larder as they went, the Clovis colonists had in about two or three centuries laid waste to the continent’s biggest mammals.

  More damning evidence indicting humans as the Pleistocene asteroid followed in the boat wakes of ancient mariners. In their explorations of the oceanic islands of the globe, humans eventually discovered New Zealand and Madagascar, and again megafaunal carnage followed. The massive moas of New Zealand, the elephant birds of Madagascar, both families characterized by the big, the meaty, and the flightless, disappeared soon thereafter.

  Whether by foul climates or foul play, the results of this pandemic of mass extinction were there for anyone to observe. In North America, the megafauna of the late Pleistocene had been extinguished by about 12,000 years ago. Which meant that by the time Columbus and company from Europe began their invasion 11,500 years later, the continent’s fauna had already been thoroughly plundered. North America had been reduced to a tattered remnant of its Pleistocene grandeur. It had become Darwin’s continent of pygmies.

  Nor were the pygmies particularly safe. “When I consider,” wrote Thoreau from mid-nineteenth-century New England, “that the nobler animals have been exterminated here—the cougar, panther, lynx, wolverine, wolf, bear, moose, deer, beaver, turkey, etc., etc.,—I cannot but feel as if I lived in a tamed, and, as it were, emasculated country … I should not like to think that some demigod had come before me and picked out some of the best of the stars.”

  The century following Thoreau amounted to a mop-up of the megabeasts. By midway through the twentieth century, the gray wolf and grizzly bear had been relegated to a class of loners, outlaws, and outcasts everywhere south of Alaska and the Canadian wilds. The secretive mountain lion survived in minimal numbers by keeping to the dark canyons and high crags, often operating under cover of night.

  As far as Paul Martin was concerned, there was only one logical conclusion for the extinction. In 1967 he went public, in the magazine Natural History. “Overkill,” rather than “overchill,” he declared, explained the missing megafauna. “My own hypothesis is that man, and man alone, was responsible for the unique wave of Late Pleistocene extinction.”

  And so the big gentle man with the impish eyes and matching streak of mischief became the prime minister of the blitzkrieg model, in which the Clovis big-game hunters, with their exquisite, deadly spear points, darted their way through the clueless megafauna of the New World, leaving behind the modern era’s paltry cast of mammals.

  But even as the quarreling paleoecologists chose their sides and dug their trenches, the leader of the overkill forces had already taken up a larger campaign. Martin had come to worry not just for the missing beasts but also for what they’d left behind. Throughout his homeland in the Southwest, the desert grasslands had for more than a century been retreating before a shrubland tide of mesquite and creosote, stems armed with thorns, leaves tainted with repellent tannins—an invading wave of defense specialists no longer thwarted by heavy browsers. Southward to Central America, fruits of tropical trees lay rotting on the ground, with no great elephantine mouths to swallow them, no giant guts to disperse their seeds in fertile piles of dung. The forests and plains with which the megabeasts had coevolved were lonely for the loss. So too were their few Pleistocene survivors. In the coastal mountains of Southern California, the last wild breeding pair of California condors—the last of the megafauna’s specialist scavengers—were to be captured in the mid-1980s and taken inside for their own good.

  “We live in a continent of ghosts,” Martin would say. “Those who ignore the giant ground sloths, native horses, and sabertooth cats in their version of outdoor America sell the place short.”

  Martin had moved beyond the question of who done it, to the suggestion that something ought to be done about it. With almost every overkill paper and presentation from 1969 onward, he began inserting a familiar closing. His bedtime story could not end so bleakly, with humans extinguishing the megafauna. It had to continue with humans bringing them back. Martin lobbied for camels and hor
ses as Pleistocene stand-ins to repatriate the Southwest scrublands. But for about thirty years, with the warring troops of overkill and overchill so busy lobbing fossil bones and radiocarbon bombs back and forth, nobody much heeded Martin’s more heretical punch lines.

  Rewilding

  In the fall of 1998, Michael Soulé and fellow conservation biologist Reed Noss proposed in the journal Wild Earth an idea that had come to be called “rewilding.” It was an idea prompted by several sobering observations on the state of modern conservation. One was that the most glorified national parks and refuges in the land, the supposed bastions of biological complexity, weren’t cutting it. Just as the tenets of island biogeography had predicted, the isolated parks—besieged at their borders by foreign species and disease, weakened from within by inbreeding among the natives, and hazardously exposed to every natural cataclysm visited upon their lonely little fortress—were being drained of wild species at rates inversely related to their size. And with few exceptions, their size was far too small.

  The other ubiquitous pitfall of the modern park, noted Soulé and Noss, was its conspicuous lack of big carnivores, itself a guarantee of attrition. Without Terborgh’s “big things that run the world,” the parks were ultimately left to the mercy of the herbivores and destined for ecological decay.

  The answer to the parks’ dilemma was a strategy niftily nicknamed the three C’s: cores, corridors, and carnivores. Protect the biggest remaining pieces of nature, multiply their effective size by connecting them one to the other, and replace their missing pinnacles—put back their missing grizzlies, wolves, mountain lions, jaguars, wolverines, or whatever top predator no longer hunted there.

  This was Soulé and Noss’s vision of rewilding, at once praised for its soaring spirit and scientific validity and drubbed for its naïve impracticality. (In addition to restocking the country with big dangerous carnivores, Noss had earlier called for at least half the land area of the Lower 48 to be included in this network.) And yet, within a year, the idea of rewilding, as Soulé and Noss imagined it, was to be dwarfed in its audacity.

  In 1999, also in Wild Earth, Paul Martin and a like-minded colleague named David A. Burney began by politely praising Soulé and Noss’s laudable ambitions. Upon which, they pushed the plunger. “Here we consider the ultimate in rewilding … We suggest that the project begin by restarting the evolution of the most influential of the missing species, the extinct animals most likely to have exerted the greatest influence on their natural environment.” There was no pussyfooting around what the two had in mind: The title of Martin and Burney’s paper blared, “Bring Back the Elephants!”

  If anyone might have doubted their sincerity, a year later Martin retested his and Burney’s elephant bomb, this time at the annual gathering of the Society of Conservation Biology in Missoula, Montana. “In the face of a radical depletion of America’s ice age megafauna we envision proactive experiments in restoration,” he said. Bison, wild horses, and camels were ready and waiting for repatriation, Martin declared. The Columbian mammoth will never again browse the western streamsides, but why not its surviving kin, the Asian elephant? How about identifying a network of large parks or ranchers sympathetic to the cause? Never mind our outdated notions of the pure and pristine. Let’s “restart megafaunal evolution in this hemisphere, and educate our children about its grandeur,” Martin admonished.

  After three decades on the rewilding stump, Martin by then had become used to the nods from colleagues who would politely clap while privately muttering away the idea as insane. This time, though, when Martin finished, he was approached by a sincere young man with light in his eyes. Josh Donlan, a recent graduate from the University of California at Santa Cruz, had already established a career of venturing where few in the mainstream of conservation dared go.

  On oceanic islands the world over, where naïve island faunas were being obliterated by shipborne invaders in the form of feral cats and rats and live-stock, Donlan and his colleagues had been devoting themselves to saving such island fauna—by annihilating their killers. Donlan in his young career had taken part in shooting more than 160,000 goats in the Galápagos to stop its famous tortoises from being run off the islands. In the Channel Islands of California, he and his cohorts had come to the rescue of a tiny seabird called Xantus’s murrelet—to the howls and lawsuits of animal rights activists—by poisoning the island’s entire population of ship rats that had been plundering the helpless birds where they nested. When Donlan happened into the auditorium to hear Paul Martin talking about putting Asian elephants in New Mexico, he had to chuckle at his own rodentine hurdles. He thought, “I got it made.”

  Donlan and Martin, conservation’s wunderkind and sage of political incorrectness, began a conversation bound to lead to bigger trouble. Their first paper together took on the status quo of their profession’s most sacred charm, the pristine myth of the year 1492. For so many in the field of conservation, Columbus’s arrival in the New World had long stood as the baseline of ecological restoration—the beginning of the demise, Eden on the brink. By Donlan and Martin’s measure, 1492 was a hollow target, a faunal façade masking a mammalian heritage already robbed of two thirds of its lineage. If restoration was honestly the goal, why not aim for the pinnacle of the Pleistocene? “The deep history of North America is commonly ignored in conservation strategies,” they wrote. “In the process of returning the California Condor (Gymnogyps californianus) to the Grand Canyon, should we also return the kinds of animals the birds once fed on?” That is, if condors, why not also horses and camels, mountain goats and elephants?

  Donlan ended up attending Cornell University, under the advisory of the evolutionary biologist Harry Greene, a serendipitous union that added yet another charge to the Donlan-Martin duo. It happened that Greene was a longtime friend and kindred soul of Martin’s, a fellow admirer of venomous snakes, an old-school naturalist, and a disciple of biological diversity for beauty’s sake.

  Nearly twenty years earlier, Greene had been among the masses in his profession who gravitated to a new book edited by Michael Soulé and Bruce Wilcox, named simply Conservation Biology. It contained a chapter in which Soulé himself took a disheartening view of conservation’s prospects. The tropics—the habitat that held nine of every ten species on Earth—were being slashed and burned at a hurtling pace. To Soulé it seemed the reserves were too small, the tropical floras and faunas too isolated, and the pace of extinctions too rapid for any new generation of species to rise from the ashes. “Thus, it would appear that with or without management, evolution of large, terrestrial organisms in the fragmenting tropics is all but over,” Soulé wrote. Or, as he and his coeditor, Bruce Wilcox, would state more wistfully in the same volume, “Death is one thing—an end to birth is something else.”

  It was the worst scenario Greene had ever imagined. And yet here, almost two decades later, in the elephantine musings of his old buddy Paul Martin, in the unjaded optimism of his new protégé Josh Donlan, was a stab at redemption. To hear Martin and Donlan talk, one began to wonder: If elephants, camels, and wild horses still lived, at least somewhere in the world, why couldn’t they live again on the continent that had birthed them? Why couldn’t the descendants of the American lion, now surviving so tenuously in Africa, be allowed to chase them on its ancestral homelands?

  The immediate answer, to most people, hardly needed stating. “Most people dismissed it as silliness,” said Greene. “But the more we talked about it, Josh and I decided it’s not silly. Let’s put together a working group. Let’s thrash it out.”

  The two assembled an eclectic team of twelve who gathered in 2004 for a long weekend at Ted Turner’s Ladder Ranch in the Chihuahuan Desert of New Mexico. Among them was, of course, the patron saint of overkill, Paul Martin, and David Burney, the fellow farsighted paleoecologist who’d seconded their irreverent paper “Bring Back the Elephants!” There too was Michael Soulé, one of the spearheads of the modern discipline of conservation biology. The roll
call also included Jim Estes, chief herald of the sea otter as marine ecology’s classic keystone predator; Felisa Smith, an expert on Late Pleistocene mammal communities of North America; Dave Foreman, former congressional lobbyist and recent founder of the Rewilding Institute, a think tank for restoring large carnivores to vacant niches of North America; Joel Berger, innovative expert on large mammal conservation, who’d once sawed horns off African rhinos to spare them from poachers; Gary Roemer, a community ecologist from New Mexico State University; and two eminent biologists from Arizona, Jane and Carl Bock, who were invited to the meeting as a balancing voice of caution.

  Over easels and PowerPoint presentations and after-hour beers, the Ladder Dozen dissected the rewilding idea, breaking it down to its factual nuts and bolts, its practical challenges and criticisms, its societal costs and benefits. They agreed on a handful of otherwise unpopular premises: that human influence had utterly pervaded the planet; that conservation’s prevailing benchmarks of purity, the 1492 landing of Columbus and the 1804 trek of Lewis and Clark, were in fact discoveries of an impoverished continent already plundered of its greatest predators and prey. Those benchmarks, at best, were rickety foundations on which to begin rebuilding the continent’s native wildness. Why not raise the standard, to that more glorious and decisive moment some thirteen thousand years ago when people first set foot in North America, when the ecology of the continent was pulsing with whole blood?

  The rewilders further agreed that the large animals’ absence was to be ignored at great peril. The fossil record was unequivocal: For much of life’s history preceding the arrival of the superpredator ape, life with megafauna had been the global norm. Forests, grasslands, and savannas had evolved in step with the Pleistocene megafauna. Their soils had been turned by trampling hooves, their seeds widely ferried and judiciously fertilized in herbivore dung. And for as long as there had been great plant-eaters, there had been great meat-eaters among them, checking their excesses, penalizing the slow and the careless.