Eric Sanderson, a scientist at the Wildlife Conservation Society, a U.S. environmental group, describes the Iberá project as hugely important. “For a long time, conservation has been about just holding the line. This project is trying to push it back out again,” he said.
Sanderson is monitoring its progress with a view to one day emulating it at the northernmost end of the jaguar’s former range — the southern United States, where the cats roamed until the 20th century.
Two-year-old siblings Juruna and Marina prowl a seven-acre pen into which a live capybara is released once a week. There are two essential elements for them to survive and thrive in the wild: knowing how to hunt and maintaining their natural aversion to the only species that threatens them — humans.
That means they may only be observed by remote camera as they jump one of the giant rodents. After some toying with the capybara, one of the cubs finally, instinctively begins the jaguar’s trademark kill technique, clamping its powerful jaws onto the back of the animal’s neck.
“They are slowly getting there,” Natalia Mufato, a biologist managing the small onsite team of veterinarians, scientists and volunteers, said. “They need to be able to kill their prey but also to do so without getting injured. A jaguar that breaks a tooth will not survive in the wild.”
The next phase for the cubs will be living in the complex’s largest enclosure, a 70-acre stretch of wetland that is already a permanent home to several capybara families. It is large enough for the felines to perfect their tracking and ambushing of prey in conditions identical to those in the wild.
When work needs to be done near their current enclosure, staff carry pepper spray and foghorns to ensure the cats do not acclimate to humans.
A key part of the project is the pool of breeding adults that were brought up in captivity in various zoos in Argentina, Paraguay and Brazil. They are too old to learn how to catch their own food but will, hopefully, continue to produce the new generation of wild cats.
Currently, three females and one male are each kept in their own spacious enclosures, packed with tall grass and trees, near enough to the cubs for the animals to be able to call out to each other.
The adults prowl excitedly as handlers approach with their food, pieces of feral pig that are still being culled to make way for native species.
The jaguars are temporarily lured into small pens while the meat is hidden around their compounds. Requiring them to sniff out the food is just one of many important details staff have developed to ensure these jaguars remain stimulated.
As the brawny cats, each weighing around 160 lbs, press up against the metal fence, their muscles ripple beneath rich dappled coats, their imposing presence almost tangible.
The jaguar reintroduction has required extensive work with local people. Jaguars actually rarely attack humans, but hunting, including by farmers concerned about their livestock, was the reason jaguars disappeared here in the first place. Given that any new felines would also stray beyond the park boundaries, buy-in from locals was paramount.
“We did a lot of work with the communities,” Mufato said. “They were actually a lot more positive than we expected. A lot of people are really proud of the jaguar.”
A local biologist surveyed 400 people in the region around the reserve and found 90 percent support for reintroducing the big cats, according to the project, which added “they also see it as a potential touristic attraction.”
Sanderson anticipates the Iberá project will work: “Jaguars are such good generalists. People think of them as living in the jungle. But the truth is they can adapt to all kinds of different habitats and prey.”
He is working, with other environmental nonprofits, on a similar project in Arizona and New Mexico, although he emphasizes that it will be years, if not decades, before the first jaguar could be released in the United States.
According to Sanderson, the U.S. Fish and Wildlife Service believe jaguars could roam as far north as Interstate 10, which runs through Phoenix, but he suspects they could go further than that, including as far north as Flagstaff, Arizona. One potential problem, given that the animals would cross back-and-forth into Mexico, would be President Donald Trump’s border wall.
“They are on a much faster track in Argentina,” Sanderson said. “But it would be wonderful to see a sustained jaguar population both in Iberá and in the U.S. once again. We have to remind people that they are part of our natural fauna and have as much of a right to be here as we do.”