The Mending

Argentina’s vast Iberá wetlands lost many of their largest species decades ago. Can an audacious rewilding plan rebuild a bygone world?

On Dahania Monsilla’s first day of work as a receptionist, she pulled on a pair of rubber boots over her khaki pants, tied her long hair into a ponytail, and set out through shoulder-high grass toward a distant line of trees. Along with a ranger, a volunteer, and me, the exploration party also included a young cook who’d begun work a few weeks earlier.

Bushwacking wasn’t exactly part of their job descriptions at Rincón del Socorro, the cattle-ranch-turned-hotel-and-nature-preserve where Monsilla and the cook worked. However, though both had grown up nearby, here in Corrientes, a province squeezed between Paraguay and Brazil in Argentina’s warm, humid northeast, they had never seen the animal they were searching for today. It had gone extinct from the province long before they were born. They couldn’t wait to be some of the first Correntinos in decades to come face-to-long-and-absurdly-skinny-face with a lost neighbor they’d never expected to meet.

Emanuel Galetto, the ranger, raised a small radio antenna above his head and listened for the clicks that would tell him which way to go. This grassland was a great habitat for giant anteaters (Myrmecophaga tridactyla), he explained, kicking open a clump of dirt and watching as ants poured out. But we were just as likely to find our quarry in the trees, where anteaters like to sleep. Sure enough, the clicks led us, slipping and ducking, toward a low section of dry forest.

Even in the sweltering December dry season, tall rubber boots are the preferred footwear for any foray into the vast region known as the Esteros del Iberá. The world’s second-largest wetland (after Brazil’s famous Pantanal) is a vast depression, a slow-moving, geological funnel left behind by curves of the ancient course of the great Paraná River, and flooded by subtropical rains. Here, what looks like solid ground often isn’t: Most of the region’s abundant water is covered in thick mats of floating vegetation, known as embalsados, sometimes rooted to the ground and sometimes floating free. Even the grasslands and forests are cut with muddy streams and sloughs, and often flooded; the rest of the region is made up of marshes and open lagoons.

Deep in the forest, Monsilla had just recovered a boot from yet another mud slick when Galetto called, in Spanish, “There she is!” I looked up to see one of the world’s strangest looking creatures ambling toward us.

The giant anteater, which Galetto introduced as Mishky, had to wear her radio-tracking device as a backpack rather than a collar because her head was so much narrower than her neck. Neck and head were one long, smooth taper ending in a small, soft, toothless mouth. Along with her tracking backpack, she wore her cub, Haku, a creature at least a third of her own size. The cub hung lazily on her mother’s back, their stripes blending into one another, and their long tails sweeping behind. Eventually Mishky seemed to tire of the weight and rolled over so that her cub fell off her back. They wrestled for a few moments and then Haku climbed right back on.

Mishky, with the characteristic comfort of an animal raised in captivity before being released into the wild, moved closer, then closer still, until she snuffled her long snout into the gap between Monsilla’s leg and the top of her rubber boot. Monsilla had officially met one of the first Correntino anteaters of her lifetime. When she looked up, she was beaming.

If you visit Corrientes now, you’ll probably see the faces of anteaters long before you make it to any marshland—they watch you from stickers on cars, from posters hung in bakery windows. Each carries the slogan “Corrientes vuelve a ser Corrientes,” which translates to “Corrientes is becoming Corrientes again.” Printed by the Conservation Land Trust (CLT), the non-profit organization that released Mishky, the posters feature a range of animals, each peering out of the land’s departed past, and promise a future that may never be realized.

Ten years ago, when CLT first bought land in Iberá, rewilding—the notion that land managers can rebuild damaged ecosystems by reintroducing species that once lived there, especially key species such as large animals and top predators, slotting them in like the missing pieces of a puzzle—was still a new idea worldwide, largely unproved, and totally untried in Argentina. “Nobody thought nature could be restored,” Sofia Heinonen, a former official with the Argentine national park system, who is now country director for the CLT, told me. “The idea was, what’s gone is gone,” she said.

A year after CLT started working in Iberá, what’s considered the founding paper about rewilding as a conservation strategy was published in the environmental magazine Wild Earth. “A cynic might describe rewilding as an atavistic obsession with the resurrection of Eden,” the authors wrote. “A more sympathetic critic might label it romantic. We contend, however, that rewilding is simply scientific realism, assuming that our goal is to insure the long-term integrity of the land community. Rewilding with extirpated carnivores and other keystone species is a means as well as an end.”

When it comes to rewilding, cynics and critics are easy to find. Objections range from the belief that it’s hubristic for people to try to direct the complexities of ecosystems as if they were our private gardens to the concern that we should actually be more actively involved. (In one project in the Netherlands, large grazing animals that had been introduced died in large numbers during harsh winters, leading to a local outcry for more assistance to animals that the project’s planners wanted to leave on their own, wild. The debate made it to Parliament.)

And CLT’s plan was unusually ambitious. Doug Tompkins, the founder of The North Face, who began CLT with his wife Kris, the former CEO of Patagonia, had followed with great interest the process of bringing wolves back to Yellowstone, and wanted to see if something similar could work in South America, where the pair had already begun buying land to donate for conservation. They visited Iberá in 1997 at the suggestion of Argentine officials, and quickly bought the ranch where Mishky would eventually be released. Though they were impressed with its biodiversity—Iberá is home to 4,000 species of plants and animals—what drew them to the region wasn’t the animals that were there. It was all the animals that were missing.

The Conservation Land Trust commissioned a study of historical and oral records and found that many large animals, once residents of the region, were now absent from the landscape—not just giant anteaters, but herbivores and fruitavores, from deer and birds to peccaries and tapirs. Large animals have an outsized effect on ecosystems, but they are often the first to succumb to human pressures—from hunting to habitat fragmentation. Without Iberá’s native megafauna to graze and poop and walk and disperse seeds, the ecology of the wetlands was subtly but fundamentally impaired.

But that didn’t mean it would be easy to put them back. In Argentina, in the beginning, distrust was high. There were questions about an American buying land in what seemed like a useless swamp. (“People generally thought there was some kind of conspiracy of the CIA,” Ignacio Jimenéz Peréz, who headed the rewilding project in its first years, told me.) Scientists doubted that animals could survive, and environmentalists questioned the wisdom of such intervention in nature.

To convince its critics, the land trust decided to start with what seemed an easy species: Giant anteaters are charismatic—they’re the symbol of a major conservation group in Argentina, giving them something of the cachet of the World Wildlife Fund’s giant panda. They’re also nonthreatening—“They don’t even have teeth,” said Heinonen—and seemed fairly simple to work with. “We looked at all the animals that used to live there, and we started with the easiest ones,” explained Peréz. Still, it took years of detailed planning before the first anteater was released. “Everything was questioned,” said Heinonen. “Everything had to be thought out.”

And giant anteaters were just the beginning. To fill all the gaps in this ecosystem, CLT would have to undertake the most ambitious rewilding plan yet seen in the Americas, working with many species at once. It would have to buy and donate land, pushing the Argentine government to permanently protect the region by declaring it a national park. (The province recently gave its approval, and Heinonen expects the national government to follow soon.) And it would have to convince locals that the plan was a good idea—that the tourism dollars such animals would bring would make it all worthwhile.

Then, too, there was the question of a top predator, absent from the region ever since the last individuals were killed sometime in the 1950s. Scientists now understand that the loss of predators has a major effect on ecosystems, causing what’s known as trophic cascade, a ripple effect throughout whatever food web the predator was pulled from.

But bringing back an apex predator to Iberá meant working with the most endangered creature in Argentina, an animal whose reintroduction would be the first in history, far more complicated and controversial than an anteater’s. It meant jaguars.

Peréz described the project’s goal to me as being, fundamentally, simple: “We want the wetlands to be whole. We don’t want them to be incomplete.” But that simple idea would prove deeply complicated to fulfill.

For humans, Iberá has long been a maze. It’s believed that the local indigenous people, the Guaraní, didn’t make homes there; they preferred more solid ground. Jesuit missionaries founded towns on the outskirts of the wetlands, near lagoons, and later residents started cattle and sheep ranches and tree plantations along the edges of the esteros—but even today, the heart of the region (and the wetlands stretch for 5,000 square miles) is free of roads or major infrastructure. Crossing means hitching a ride in a plane or going the long way around.

For a long time, the region’s inaccessibility allowed it to remain a paradise for animals. But its solitude was no match for a fashion craze a continent away.

In the late 1800s, Victorian fashion demanded large amounts of plumage to decorate women’s hats—not just feathers, but wings and even whole taxidermied birds. William Temple Hornaday, the conservationist and taxidermist, calculated that it took 130,000 dead egrets just to supply the London plumage market for one nine-month period. The price of an ounce of feathers eventually matched that of an ounce of gold. In Corrientes, as in many parts of the Americas, hunters took heed.

Iberá is home to three species of white egret—and five of herons, five of ibises, three of storks, and so on—nearly 400 species of birds altogether, including colorful parrots and parakeets. But the hunters who pursued them—known locally as “mariscadores,” which translates roughly as seafood-hunters, a reference to the aquatic environments they hunted from canoes—found the region full of many other animals whose pelts or skins they could sell, especially as the plume trade diminished. They spent months deep in the wetlands, with guns and traps, eventually emerging with the skins of capybaras (Hydrochaeris hydrochaeris, the world’s largest rodent, growing up to 180 pounds), as well as of giant otters (Pteronura brasiliensis), caimans, tapirs (Tapirus terrestris), and jaguars (Panthera onca).

Hunting wasn’t the only peril for Iberá’s native wildlife. Invasive species—including wild pigs and deer introduced for hunting, and plants brought in for plantations—crowded out natives or altered the ecosystem. Plantation owners growing rice, pine, and eucalyptus built canals that drained water from the wetlands, and they used chemicals, including sulfuric acid, that leaked into and poisoned the waterways. Ranchers regularly set fires to promote tender grasses for their domestic animals. Pampas deer (Ozotoceros bezoarticus), which once roamed Argentina’s vast plains by the millions, died of diseases they caught from introduced cows and slowly lost their grazing lands to livestock.

By the early 1900s, green-winged and glaucous macaws (Anodorhynchus glaucus, named for their all-blue plumage) were no longer seen in Iberá. The last jaguar was recorded in the 1950s, and the last tapir in 1974. By the 1980s, the pampas deer was extinct from Iberá; the jaguar, tapir, peccary (Pecari tajacu), giant anteater, and muitu (Crax fasciolata, a bird) from all of Corrientes; and the giant otter and green-winged macaw (Ara chloropterus) extinct from all of Argentina. The glaucous macaw was just extinct, period.

In 1983, Corrientes declared Iberá a provincial reserve, with hunting outlawed. Some of the mariscadores, who knew the place best, even became rangers. Soon, managers noticed something interesting: animals whose populations had crashed but were still hanging on—including capybaras, caimans, and egrets—began to recover, and then to thrive. Today, they’re everywhere. On my first evening in Iberá last December, I went for a short walk and watched egrets resting in a copse of trees; a young fox trotting through the grass; a marsh deer (Blastocerus dichotomus) with an impressive rack of antlers standing deep in mud; perhaps a dozen rheas (Rhea americana, South American relatives of ostriches and emus) grazing, running, and fluffing their feathers; and scores of round-bellied, square-faced capybaras. Babies nursed in packs beneath their mothers, whole families wallowed in the mud holes that they’d dug to escape the heat, and an adult male snorted at a caracara (Caracara cheriway), a large bird similar to a falcon, that attempted to perch on its back.

There was, of course, no comparable recovery of jaguars or tapirs or macaws or peccaries, or any of the other species that had already been extirpated from the landscape. It’s a tenet of conservation biology that, once threats are removed and habitat restored, animals will repopulate the area. This is sometimes called the “field of dreams” myth: Build it and they will come. But as Mauro Galetti, a Brazilian conservation biologist and proponent of rewilding has written, that formula can only work if species are still present to repopulate.

Galetti is perhaps most famous for proposing in 2004 that the plains of South America be rewilded with modern animals that could fill the ecological niches left behind by the Pleistocene megafauna that went extinct there long ago. Such proposals generated criticism that they were unrealistic, and that they ignored all the ways ecosystems have changed in the intervening millennia. Galetti is now advocating for what he calls “a less radical type of rewilding”—reintroducing, from zoos and other populations, species that are only locally extinct.

The day after meeting Mishky, I piled into a truck with Monsilla, the curious receptionist; Galetto, the young ranger; and Sebastián Di Martino, the affable, unceremonious leader of the rewilding program. Just returned from another part of the reserve, Di Martino wore a few days’ growth of graying beard, a striped t-shirt, and glasses that fogged in the damp air. Like Heinonen, Di Martino worked for parks elsewhere in Argentina before coming to Iberá, and he spoke of his troublesome new charges with rueful affection, often heavily peppered with Argentine slang. “In other places, like Patagonia, the important things are the landscapes,” he told me. “Not here. Here it is the biodiversity, the species, that people will come to see.”

The truck turned down a rutted gravel road. It was the three-week anniversary of the first day that the first two tapirs in recent history had roamed wild in Iberá, and we were off to see how they were getting along.

After another long, slippery search with the antenna, we were zeroing in on the male of the pair in a region of dry forest when suddenly he charged out of the underbrush right by us—a bit of a jolting sight, since an adult tapir may weigh as much as 500 pounds. (Horses, donkeys, and rhinoceroses are the species’ closest, though still distant, relatives: Tapirs have three-hoofed toes and a short, agile snout a bit like an elephant’s trunk.) This one waggled his snout at us. “Francisco!” cried Di Martino. “Che! How are you?”

Other than a sore spot where his tracking collar was rubbing into his left ear, Francisco was doing fine, and seemed to be happy to see us. He’d gotten used to Di Martino while held in quarantine and then during weeks spent acclimating to the area in a large pen. Di Martino fed him fruit from a plastic bag and scratched his back with a stick; within a few minutes, to my surprise, Francisco flopped onto the ground and presented his belly for scratching. “Can you tell he’s a zoo animal?” asked Di Martino, as he obliged the huge, happily squirming tapir. “They are not wild animals, even if they live in the wild.”

If rewilding sounds easy—find some living animals of the species that you’re missing, drop them off, they go wild, and the ecosystem rebuilds itself—Iberá is a good lesson in the challenges, especially when you don’t have access to actual wild animals.

In other rewilding projects, such as in southern Africa, it’s common to translocate wild animals from healthy populations into new areas. But Argentina does not permit such moves; its leeriness, Di Martino speculates, dates to a botched operation in the 1970s that led to the deaths of all the pampas deer involved. Nearly all of the animals that CLT has relocated to Iberá—which now includes giant anteaters, pampas deer, collared peccaries, tapirs, and a few maned wolves, with macaws and jaguars in process—are zoo animals, or at least raised in captivity. (The pampas deer and maned wolves, which had close enough populations that they only needed provincial authority to relocate, are the exception.) Most of the anteaters come from other provinces where, as babies, they were orphaned by hunters who then adopted them as pets. CLT has cultivated networks of teachers, police, ranchers and other contacts to let them know when a family has a baby anteater, which usually dies within a few days without proper care. They try to convince the families to let them raise the animal and return it to the wild instead.

But working with captive animals is a major challenge. It’s not just the cost—though they have to be kept in quarantine to make sure they don’t spread diseases, which means significant expense in personnel, medicine, and food. It’s how unprepared the animals are to be wild creatures. They don’t know how, and so, improbably, they have to be taught.

For the tapirs, that meant months in a pen, acclimating to their new food sources, and regular monitoring of their weight and their wanderings. The female, Nato, had been repeatedly spotted close to a road at night; Di Martino, who wasn’t sure what drew her there or how to stop her, decided to put a reflective strip on her tracking collar so she wouldn’t be killed by a car. But tapirs are relatively easy: Adults have no predators to fear in Iberá, and they at least know how to walk and eat.

Macaws, on the other hand…

“They don’t know anything,” says Di Martino, in amused frustration. “They are a disaster. You have to teach them how to fly.”

That week, CLT had nine macaws prepping for release in an enclosure on the far side of the reserve. A year before, they’d released seven others, and it hadn’t gone well: Three were eaten, probably by a small wild cat called a Geoffroy’s cat, three were lost, and one was recaptured. They’d all come from zoos, which commonly keep birds in small cages where they hop instead of fly and eat whatever the zookeepers give them. In the wild, they were hopeless.

Not wanting to take any more chances, Di Martino and his team started training the next group six months earlier. They put native foods on either side of a large enclosure, forcing the birds to develop their muscles by flying back and forth. They added obstacles for the birds to swerve around, and then more complicated routes to get food. They replaced sturdy branches with weak ones, so the birds would learn to be cautious about where they landed. They got a taxidermied macaw and trained a harrier to attack it, and then made the other macaws watch, to teach them to recognize and fear potential predators.

Now they were finally ready to leave one of the doors of the enclosure open to see what the birds would do.

As challenging as macaws and tapirs are, they have nothing on jaguars. It’s one thing for a tame tapir to ask for a belly rub. It’s quite another to release a habituated jaguar—an animal known for a bite so strong it pierces skulls—that associates humans with food.

Deep in the reserve, on an island, in an area only accessible by plane or boat, lived the first two jaguars to set foot in Iberá in fifty years, Tobuna and Nahuel. They arrived from zoos in Argentina in 2015 and 2016, and were already local celebrities—one regional paper gives its readers regular updates on their “historic romance” and “passionate encounters,” as if they’re characters on a soap opera. (It doesn’t seem to have mentioned, though, that the first time the jaguars were put in the same enclosure, Conservation Land Trust staff were standing by with air horns, tranquilizing darts, a fire extinguisher, doors—anything that would allow them to intervene if these precious, long-awaited assets decided they’d rather kill each other than mate. They chose to mate.)

Neither jaguar is wild enough to ever be released; the hope is that they’ll create a cub that will be. So far, no luck. Twelve years old when the paperwork to move her began, Tobuna is now 15, on the upper edge of her fertility; Nahuel has not been previously documented to have sired a cub. But the options were limited—in the last 10 years, according to Di Martino, 10 of Argentina’s 40 zoo jaguars died, and no new ones were born. Those that remain are largely interrelated. During my visit, CLT was at work getting permission to bring in a new pair—a female from Brazil and a male from Paraguay.

When and if a cub is born, that’s when the real complexity begins: A jaguar that will live in the wild can’t be familiar with humans, so before the pregnant mother gives birth, she will be moved to a much larger enclosure, one where live prey (starting with those fat and abundant capybaras) can be stealthily introduced.

If Tobuna gives birth to Iberá’s first native jaguar of the century, she’s the one who’ll have to teach it to hunt—which is why it’s good that she’s finally had a chance to learn herself. In the zoo, she ate dead meat; when she met her first live capybara, she made a bloody mess as she tried to figure out how to kill it. “It was hardly worth seeing,” said Di Martino. “She played with the capybara. Now she kills the capybara perfectly.” For a jaguar, that means quickly crushing the skull at the back of the neck with her powerful jaws.

When the new jaguar has learned to hunt, it will be moved to an even larger enclosure, 30 hectares and already full of capybaras and deer, where it will hunt for itself until it’s large enough for the adult-sized tracking collar it will wear in the outside world. Then, theoretically (CLT currently has a permit to breed jaguars, but not yet one to release them) it will be released into a world perfectly suited to its skills. Jaguars are a rare cat that loves water; they even like to stalk and eat caimans, which in Iberá can grow to nearly 10 feet.

There are only an estimated 200 jaguars left in all of Argentina, where 95 percent of their former habitat has been destroyed. A recent study estimated that Iberá can support up to 100 individuals. But achieving that number is a very long way away.

Eventually, CLT’s plan is to translocate wild jaguars to build up genetic diversity—but not until they’ve established a core population with the heart of its territory deep in the reserve, far from people. That’s both to help with the permitting, and to make the jaguars more welcome among their new neighbors. One survey found more than 90 percent local support for returning them to the wild, but ranchers elsewhere in South America are known to kill jaguars that attack their cattle. Di Martino worries that, “when the cubs grow and we open the doors to the pen,” fear could change those numbers dramatically, unless people are already personally invested in the lives of Tobuna, Nahuel, and the jaguars to follow.

“Here, we go very slow, because we’re telling people a story,” Di Martino told me. “It’s like a love story: the first jaguars that are Correntinos.”

The following day, Heinonen, Di Martino, and Pascual Peréz, who will be the director of the new national park in Iberá once it’s officially approved by the national government, waited out a thundering rainstorm in the lobby of a new hotel on the far side of the reserve. The hotel, whose modernist architecture stood out dramatically from the more modest buildings of the small agricultural city that surrounded it, was named Tobuna Suites, after the jaguar. It was mostly empty.

“We’re prepping for when the tourists come,” said Peréz. “They’re not here yet.”

They’d come to the city (known both by its Spanish name, Concepción, and its Guaraní one, Yaguareté Corá, which means corral of the jaguar) because it was the one-year anniversary of Douglas Tompkins’s death in a kayaking accident, and the town—one of the “portals” to the reserve that hopes to prosper when the tourists come—wanted to honor him during its annual festival for the Day of the Virgin. In a churchyard and community center down the street from the empty hotel, a small army of volunteers stood ready with tray after tray of food, preparing to feed the hundreds of people who had gathered for the celebration. (One man whose nametag said “barbecuer” in Spanish told me that to feed the crowd the town had butchered 38 cows, in addition to the stacks of coiled sausage and massive pots of a stew made with polenta, chicken, and cheese.) The priest of the local church stepped onto a small stage beneath a mango tree to give a speech.

“A cabybara is worth more alive than dead,” he pronounced, after presenting Heinonen with a plaque to give to Kris Tompkins and quoting from Pope Francis’s encyclical on the environment. (Francis, the first Argentine pope, is a popular subject of discussion in this heavily Catholic country.) “A dead capybara is worth the skin on his back,” continued the priest. “A live capybara is worth, ten, one hundred, a thousand photos before it dies of old age.” The people, many dressed in the traditional ranching attire of gauchos, applauded politely and then dug into their lunch.

Later, driving from the celebration to the quarantine station to check on two new tapirs waiting for their chance to be released, Heinonen reflected on the Pleistocene animals whose absence Mauro Galetti, in his early proposal for South American rewilding, had regretted. “We’ll never get that back,” she said. “But this is an extinction that’s recoverable.”

After a few months of support and a few years of monitoring, Conservation Land Trust’s method is to back off and leave the introduced animals alone. Mishky is the only anteater that still wears a tracking device; the other sixty or so anteaters that live near here are doing their own, invisible thing. A new population, in a different part of the reserve, now has 27 members. A second population of pampas deer is waiting to be released.

In December, 14 new peccaries were released from quarantine, and the first macaw left the enclosure where it had been trained. At first the staff, which had expected the macaws to only fly out and back in, were afraid for it, and tracked it into the forest, but after a month of survival decided it was out of their hands. They see it fly by from time to time.

In mid-January, a new resident arrived from a reserve in Paraguay. He was Chiqui, Iberá’s third jaguar. Di Martino was thrilled. But he was also already thinking about a new discussion among CLT staff: what it would take to bring back ocelots and giant otters, two other species that disappeared from Iberá long ago. “I think we will do it,” he said. “The environment works better with all the pieces in place.”

Additional photo credits:
Header image of Nahuel by Karina Lerdrup Spørring
Two photos of Iberá wetlands as seen from the air by Mike Unwin
Southern Rhea (flightless bird) by Mike Unwin
Typical Iberá tree by Brooke Jarvis
Adult female jaguar Tobuna on climbing structure by Karina Lerdrup Spørring
Closeup of adult male jaguar Nahuel by Karina Lerdrup Spørring
Footer image of adult female jaguar Tobuna with radio collar by Kariana Lardrup Spørring

Brooke Jarvis

Brooke Jarvis is a magazine journalist based in Seattle, Washington, and a regular contributor to The New York Times Magazine and The California Sunday Magazine. In 2016, she received the Reporting Award from New York University's Arthur L. Carter Journalism Institute, and was a finalist for the PEN USA Literary Award in Journalism and the Livingston Award in International Reporting. She is a visiting scholar at NYU.

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