A hoarse, yelping bark rang out from the wooded hillside. Then again. The unearthly calls, sounding somewhere between fox and cat, continued in a steady sequence, carrying through the forest’s mossy tree trunks and damp leaf litter, growing louder as they approached. Then, abruptly, the woods fell silent.

“I knew he must be close when the call stopped,” explains French wildlife photographer Laurent Geslin, recounting the moment in January 2011 when he first laid eyes on a wild Eurasian lynx. “I knew that he must have seen me.” Geslin, who has spent the past six years pursuing this elusive beast through Switzerland’s Jura Mountains, was confident that the cat, though shy, would be curious. All he had to do was keep quiet and watch.

“I checked every tree and every branch,” Geslin recalls. “And then I checked again.” He explains how a lynx’s lightly marked grey-brown coat blends so perfectly into the dappled backdrop of rock, leaf and shadow that it can disappear in plain view. This time, however, his diligence paid off. One final binocular sweep in the fading light at last revealed those telltale cat contours, materializing from the abstract backdrop like an optical illusion. “He was about 25 meters away, sitting on his backside, looking very calmly at me.” Geslin’s voice still betrays the excitement. “It was a great sensation.”

A camera trap captures the image of a female Eurasian lynx, known to biologists as “B218,” with the lights of Yverdon-les-Bains, Switzerland in the distance.
A camera trap captures the image of a female Eurasian lynx, known to biologists as “B218,” with the lights of Yverdon-les-Bains, Switzerland in the distance.

Since then, Geslin has notched up about 30 precious sightings, ranging from distant glimpses to, on one memorable occasion, a mother leading her three cubs to feed within meters of his hide. This total might seem a modest return for six years of searching—six years of pursuing every clue, staking out every hideaway, and sitting in hides for 96 hours at a stretch. But few people anywhere have enjoyed such success.

Having spent years photographing big cats around the world, Geslin was amazed to find how little was known about the one living on his own doorstep. His book, Lynx: regards croisés (“different perspectives”), published in France in 2014, is the first full photographic study of this species in the wild, and testament to his extraordinary dedication and perseverance.

Just a few decades ago, such a project would have been impossible. The lynx had not been seen in Switzerland since 1904. Once common across much of Europe, it had also disappeared from France, Germany, and many other former strongholds. By 1940, the continent’s entire population had fallen to an estimated 700 animals, confined largely to the wildest reaches of Scandinavia. This sorry tale mirrored that of the lynx’s fellow large carnivores, the wolf, wolverine, and brown bear. All had declined dramatically in Europe, victims both of ruthless persecution— either for sport or because, as hunters of wild game and occasional livestock killers, they were viewed as competition—and the relentless destruction of their natural habitats.

An adult female Eurasian lynx is released in Kalkalpen National Park as part of a continuing effort to reestablish healthy populations of the species in western Europe.
An adult female Eurasian lynx is released in Kalkalpen National Park as part of a continuing effort to reestablish healthy populations of the species in western Europe.

In the 1970s, however, scientists began a pioneering project to reintroduce the lynx to Switzerland, focusing their efforts on the Alps and, a little farther north, the Jura Mountains. Some 30 animals from the Carpathians were, over time, introduced to the Jura, founding a population that has since grown to 130 and spread unassisted into neighboring France. It is these animals that Geslin has been studying, working closely with Swiss-based carnivore conservation group KORA.

The lynx reintroduction project forms part of a larger “rewilding” initiative, of which KORA is a leading proponent. By returning Europe’s native large mammals to the landscapes they once roamed, scientists hope to recreate something of the natural environment that carpeted Europe before humankind began felling forests. Predators, according to the basic laws of ecology, are essential to the healthy functioning of any natural habitat. Remove them and prey species soon proliferate, leaving the environment in much worse condition for everything else that depends on it. “In the nineteenth century the Jura forests were strongly over-exploited and all large mammals, including wild ungulates, became virtually extinct,” explains Urs Breitenmoser, KORA co-founder. Then in the 20th century, without predators around, wild ungulate populations—including red and roe deer and wild boar—rebounded. So much so that their numbers are unsustainable and regularly cause significant ecological damage. Many other regions around Europe are suffering similar effects from burgeoning deer population.

The classic example of how bringing back predators can turn things around is Yellowstone National Park—where, in the 1990s, wolves were reintroduced after 70 years of absence. Elk numbers have since fallen to sustainable levels, allowing overgrazed vegetation to recover, beavers to return, wetlands to develop and ground-nesting birds to thrive. Not all the complexities of this “trophic cascade” are fully understood, but ecologists generally agree that wolves have transformed Yellowstone’s ecology, restoring the park’s ecosystems in a way they had not dreamed possible. 

Three bewildered Eurasian lynx cubs peer out from their den after being discovered by KORA conservation biologists.
Three bewildered Eurasian lynx cubs peer out from their den after being discovered by KORA conservation biologists.

But central Europe is not Yellowstone. How, one might reasonably ask, can we bring back large predatory mammals that long ago proved incompatible with people to a region that has only become more populous since the animals disappeared? If there was no room for these predators before, surely there is even less of it now. 

The answer lies in the nature of the animal itself. The Eurasian lynx (Lynx lynx) is a formidable predator. Though not technically a big cat—it doesn’t sit alongside lions and tigers in the genus Panthera—males can nonetheless top 30 kg (65 lbs), almost twice the weight of the superficially similar Canadian lynx (Lynx canadensis). This gives it considerable predatory punch, allowing it to subsist not—like other lynxes—on rabbits and hares, but on hoofed mammals such as roe deer. What’s more, this is an animal of almost preternatural stealth. Wherever it occurs, it nearly always remains well out of sight.

Reintroducing the lynx, therefore, is a very different proposition from bringing back wolves and bears—schemes that have met stiff opposition across Europe. Though large enough to have a significant influence on ecology, the cat will slip silently into the woods the moment it is released, never to be seen again, except by the most dedicated. It is thus what scientists call a “soft” predator, representing no perceived threat to the public and so prompting none of the fuss generated by the likes of wolves. “For most people,” explains Geslin. “This cat is like a ghost.”

KORA biologist Fridolin Zimmerman subdues an adult female Eurasian lynx in preparation for the animal’s relocation to Kalkalpen National Park, Austria.
KORA biologist Fridolin Zimmerman subdues an adult female Eurasian lynx in preparation for the animal’s relocation to Kalkalpen National Park, Austria.

But while the animal slips under the radar of most of its human neighbors, the foresters are beginning to notice a difference, with roe deer populations thinning out and forests showing signs of regeneration. It is not simply that lynx keep deer numbers down. After all, there are only so many deer a handful of lynxes can catch and eat. It is also that the herbivores’ behavior changes when a predator is around. They gather in smaller numbers and, ever alert to possible attack, become more mobile, less inclined to linger in feeding areas. Just the scent of a lynx’s territorial markings on a trailside tree trunk can be enough to keep them on the move. Park rangers, Geslin reports, wish more of the cats could be introduced. “They tell me that since we’ve had lynx they never have any problems.” 

For the cat, however, problems remain. Livestock farmers are rather less welcoming than conservationists. It is true: lynxes can, and occasionally do, take sheep. However, studies have shown that the cats much prefer wild prey. As forest ambush predators, they are not adapted to hunting in the open. Only in Norway, where sheep roam forested areas unmanaged, have significant losses been recorded. Elsewhere, including in Switzerland, predation has had negligible impact. Further studies have shown that appropriate management measures—for example, grazing sheep away from forest edges—make a big difference. The World Wildlife Fund (WWF) is among the conservation organizations promoting new livestock management strategies in the Alps, including the use of specially trained guard dogs and protective fences, that help reduce conflicts between lynx and livestock herders.

Biologists work quickly to collar, measure, and take tissue samples from an anaesthetized adult Eurasian lynx in the Swiss Alps.
Biologists work quickly to collar, measure, and take tissue samples from an anaesthetized adult Eurasian lynx in the Swiss Alps.

Hunters, unfortunately, are harder to convince. They see the cats as competition, arguing that roe deer and chamois—a goat-like antelope native to mountainous areas of Europe—have become much harder to hunt now that lynxes keep them more wary. Breitenmoser points out that Swiss law protects not only lynx but also the right of hunters to harvest wildlife. “Unfortunately such situations regularly lead to conflicts,” he explains, “including illegal killings.” The female with cubs that Geslin observed and photographed fell victim to a hunter’s rifle just one month later. Another reintroduction program in the Vosges, just south of the Jura, has failed, with the last individuals killed by hunters. “No lynx population in Europe will survive,” warns Breitenmoser, “if hunters actively oppose it.”

Scientists also worry about the dangers of inbreeding. The reintroduced lynxes have not dispersed as far as was hoped. Penned in by roads and development, they have tended to stick to the areas into which they were first introduced. Given the very small number of lynxes from which today’s population is descended, this has raised the threat of inbreeding and a prospect of genetic problems for future populations. While things are better in the Jura than in some other reintroduced lynx populations, the problem will need to be addressed in the long term by increasing connectivity between isolated populations: “Links for the Lynx,” as WWF calls it.

A wary, and bloody, adult Eurasian lynx drags a fresh kill to a more secluded location.
A wary, and bloody, adult Eurasian lynx drags a fresh kill to a more secluded location.

Nonetheless, KORA deems the program a success. From those first 1970s releases, there are some 130 lynx in the Jura today. The effort has now been extended to other areas of the country and lynxes have expanded their range, naturally, into France. Recently, KORA has also relocated individual lynxes into both Austria and Italy, and a further relocation into Germany is in the pipeline. “Lynx have demonstrated that they can live well in a human-dominated environment, such as the Jura,” confirms Breitenmoser. “So the argument that they can no longer survive in our modern world has mostly disappeared.”

Meanwhile, lynx numbers elsewhere in Europe continue to rise. The overall population is now estimated at around 9,000, with the largest concentrations in Finland and the Carpathians. This population is made up of 11 key groups, spread across 23 countries. Only five of the groups are native—indicating the success of reintroduction efforts. The Lynx UK Trust now hopes to reintroduce the cat to Britain, where it was last seen in AD700, and where the environment is in serious need of a predator to control its rampant deer populations. Surveys indicate 91% public support for the idea, with trials proposed for 2017.

Even lynx cubs must be handled with great care. KORA biologist Andreas Ryser swaddles this three-week-old youngster in preparation for weighing, measuring, and releasing the cub back into its den.
Even lynx cubs must be handled with great care. KORA biologist Andreas Ryser swaddles this three-week-old youngster in preparation for weighing, measuring, and releasing the cub back into its den.

The lynx’s future depends upon cross-border cooperation. No single country in central Europe can support a viable population alone. A critical factor to date has been the EU Biodiversity Directive, which compels all member states to protect and restore populations of rare species. Only with this cooperation, Breitenmoser believes, can the scattered populations become better connected, allowing a flow of lynxes over a broad enough area, and reduce inbreeding. “We need the distribution to be broader,” he explains, “but the local abundance to be more limited.”

Meanwhile, the lynx’s enemies must still be won over. This will take education, overturning traditional antagonism towards predators, and convincing the public at large of how the cats benefit the environment for everybody, including hunters. It’s a long process and not something KORA and other conservation bodies can accomplish without political support.

A female Eurasian lynx, known to biologists as “B123,” surveys her territory with her two cubs in Switzerland’s Jura Mountains.
A female Eurasian lynx, known to biologists as “B123,” surveys her territory with her two cubs in Switzerland’s Jura Mountains.

Out in the forest, Geslin’s mission continues. Tramping the trails daily in search of tracks and kills, checking his camera traps and setting up his hides, he is learning ever more about this most private of cats. When KORA researchers take to the field—to monitor the lynxes, study their movements through radio telemetry or even capture one for a GPS collar or translocation elsewhere—he is always close by with his camera to record the action. 

These are the memorable days—examining a sedated cat or photographing a relocated individual bounding away into its new home. Most of the time, however, things are not so easy. “Days become weeks and weeks become months,” Geslin says. “But then I hear a strange call or notice a slight movement and all the waiting vanishes.” The rewards make the long, lonely vigil worthwhile. “After all,” he confirms, “you just cannot beat a lynx.” 

A version of this story originally appeared on bioGraphic.com.