Conservationists first spotted a young male jaguar in 2022 roaming Argentina’s Formosa Nature Reserve. Camera traps later recorded the same individual in a forest tens of kilometers away, within El Impenetrable National Park, in northern Argentina’s Chaco province. After months of tracking, an expert team located the big cat and, in December 2024, sedated, collared and released it back into the wild. They gave it the name Tañhi Wuk.

This marked another milestone in Argentina’s broader efforts to protect its small population of jaguars (Panthera onca), led by a team from El Impenetrable National Park, Formosa Nature Reserve, and the Rewilding Argentina Foundation, with support from biologists and veterinarians. These reserves, along with others such as the Iberá National Park, form part of the Gran Chaco, South America’s second-largest forest (after the Amazon) and yet one of its least protected. 

Poaching and habitat destruction over the last 40 years have decimated wildlife populations in the biome. But conservationists are working to reverse the trend. Collaring is a key part of jaguar conservation, providing vital data to guide protection efforts. Tañhi Wuk is the third collared male in El Impenetrable, bringing the total number of monitored jaguars there to five, including two females introduced last year. GPS tracking shows Tañhi Wuk hunts along the Bermejo River and crosses into Formosa province; both areas are threatened by illegal fishing and poaching. 

The tracking data help researchers intervene when jaguars leave the park, notifying landowners, educating them about the species, and offering support if livestock are lost to jaguar attacks. In some areas, researchers even camp overnight to monitor hotspots where jaguars might be at risk. 

To prevent retaliation from landowners who lose livestock, researchers engage with local communities, educating them about the legal protection jaguars have. For example, in 2001, Argentina declared jaguars a national natural monument, meaning harming one can lead to hefty fines or jail time. 

“Every jaguar is like a moving national park,” Guillermo Díaz Cornejo, a lawyer and a member of the board of directors at Argentina’s National Parks Administration, told Mongabay. “You cannot touch it, you cannot interact with it.” 

Collars also help deter poaching by making jaguar deaths more visible, according to Sebastián Di Martino, conservation director at the NGO Rewilding Argentina. “If a collared jaguar is killed, it makes headlines. If an uncollared one is killed, it often goes unnoticed,” he told Mongabay. 

Across the Gran Chaco, which straddles the border region between Argentina, Paraguay, Bolivia and Brazil, the greatest threat to jaguars is conflict with humans. Last year, an uncollared male jaguar was shot and skinned by hunters in Argentina. Meanwhile, a male collared in El Impenetrable in 2019 has survived despite roaming poaching hotspots, including private cattle ranches. “The collar has likely helped protect him,” Di Martino said.

Boosting genetics

Collaring males like Tañhi Wuk is just one of several current initiatives to protect jaguars and restore the Gran Chaco’s ecosystems. This March, conservationists at the Rewilding Foundation and supporting partners will take another critical step: releasing Mini, a female jaguar, into El Impenetrable.

“It is necessary not only to increase genetic diversity, which is always good, but above all to boost reproduction,” Gerardo Cerón, a biologist involved in Rewilding Argentina’s projects, told Mongabay. “We need more jaguars, and for that, the best option right now is to bring in females.”

Two females were previously released into El Impenetrable in 2024: one born in a forested enclosure set up by NGO Rewilding Argentina and another rescued and rehabilitated from Paraguay. Mini will be the third. But her case is unique.

Born wild in Iberá National Park, Mini comes from the world’s first jaguar reintroduction project. Jaguars had gone extinct from the park 70 years ago, but since conservationists began restoring the species in 2021, Iberá’s jaguar population has grown to between 35 and 40 individuals spanning three generations, making it a promising source for rewilding other regions.

Mini’s move is groundbreaking. She’s the first jaguar translocated from one wild population to another. In Argentina, this is also the first wild-to-wild translocation of any mammal, bird or reptile. The process required special permits from Argentina’s National Parks Administration, which had never before authorized such a transfer.

“We’re trying to mimic the natural translocation that would happen if Argentina still had the natural corridors that would protect the communications between populations,” Cornejo said.

Conservationists closely monitor jaguar genetics to prevent inbreeding. Before translocating Mini, they ensured she had enough genetic diversity to strengthen the population. The National Parks Administration conducts extensive research before authorizing jaguar translocations. This involves consulting experts — mainly from Brazil, home to the world’s largest and most stable jaguar populations — who include biologists, geneticists and conservationists. In the case of Mini, the process took at least six months of study before approval.

Translocations are vital because jaguar populations are often isolated by human-made barriers like cities and highways, Cerón said. This isolation leads to fragmented populations that breed among themselves, causing a loss of genetic diversity over generations. Inbreeding diminishes adaptability to climate change impacts, diseases and other challenges.

“To achieve good genetic diversity, translocations are the most efficient method,” Cerón said.

If successful, Mini’s journey could pave the way for more wild-to-wild translocations as a quicker alternative to captive breeding.

“Instead of resource-intensive breeding programs, relocating wild individuals could be a more efficient way to restore jaguar populations,” Di Martino said. “If we want to bring jaguars back to other parts of Argentina — or even to regions where they’re completely extinct, like the southern U.S. — wild-to-wild translocations are the future.”

Making a corridor

Conservationists are exploring ways to connect jaguar populations across Argentina, Paraguay, Brazil and Bolivia. The goal is to establish safe passage along key waterways where forests are better preserved and wildlife moves naturally. While there’s no set timeline for when this might begin, discussions and planning are underway to turn this vision into reality. This would help link restored populations in northeastern Argentina, such as those in Iberá and El Impenetrable.

Historically, jaguars roamed as far south as northern Patagonia, but in Argentina, their range has shrunk by more than 95% in the last 150 years. Only about 200 of the big cats remain in the country, with populations in Paraguay and southern Brazil also in decline. This isolation has created fragmented groups with no genetic exchange between them.

“We have isolated populations of jaguars, like islands,” Di Martino said. “They don’t have contact with other populations of jaguars. So we need to start connecting these populations.”

The initiative could benefit not just jaguars but also species like giant otters (Pteronura brasiliensis), giant anteaters (Myrmecophaga tridactyla) and Pampas deer (Ozotoceros bezoarticus), whose populations are similarly isolated. 

International collaboration will be crucial to making this vision a reality. Efforts to connect these populations will depend on working with local communities in the unprotected spaces in between parks and reserves, helping them coexist with jaguars by mitigating livestock losses and fostering tolerance.

“This is a key concept behind the corridor,” Di Martino said. “If we manage a protected area well, it can become a source of animals to reintroduce into regions where species have disappeared.”

By opening up new areas for jaguars, these efforts could also benefit the communities in those regions. Iberá is a key example of how conservation has driven economic transformation. Once devoid of wildlife, local populations have built new livelihoods around tourism.

“We work closely with communities to create an economy built around wildlife,” Di Martino says. “In Iberá, tourism is now the main economic driver, and that’s thanks to jaguars.”

Conservation across Latin America faces systemic barriers, as the traditional model of protecting land and expecting nature to heal itself isn’t enough, Di Martino said. Interventions like translocations and captive breeding are needed, but they run against the idea that human interference should be kept at a minimum. Strict regulations further slow progress. In some countries, wildlife laws prevent species from being moved across borders, stalling efforts to link jaguar populations in Paraguay and Bolivia.

For Di Martino, part of the long-term success of widespread jaguar conservation depends on a shift toward adopting a conservation approach that embraces hands-on restoration, such as collaring jaguars like Tañhi Wuk and wild-to-wild translocations.

“If you manage a protected area well, it can be a source of animals to recover species in other places where they went extinct,” Di Martino said. “These national parks were great, but depleted of wildlife. Now, as we recover the ecosystem, the story is changing dramatically.”

Banner image:Mini, a wild female jaguar, was relocated from Iberá National Park to El Impenetrable National Park to help restore the local big cat population. Image © Sebastián Navajas/Rewilding Argentina Foundation.

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