In 2005, conservationists tackled Atlantic Forest loss after more than 80% of its woodland had vanished. 13 years later, jaguars in Upper Paraná rose 160% to 105 animals

In 2005, conservationists stepped up efforts to protect Brazil’s Atlantic Forest after more than 80% of its original woodland had disappeared. The damage had left wildlife with shrinking and fragmented habitats, making recovery a difficult task. Yet 13 years later, signs of progress were visible in the Upper Paraná Atlantic Forest.

Jaguar numbers rose by 160%, increasing from about 40 animals in 2005 to an estimated 105 in 2018. The recovery reflected years of habitat protection and improved forest connectivity. For conservationists, the increase offered a rare example of how sustained efforts can help threatened wildlife regain ground.

Cross-Border Conservation Brings Atlantic Forest Jaguars Back

Population monitoring began in 2003, when researchers were already concerned about the jaguar’s future. Government agencies, scientists and conservation groups then worked together on monitoring, habitat management and public education.


Between 2006 and 2018, those efforts helped double the jaguar population in Misiones. By 2018, researchers estimated that about 105 jaguars occupied the monitored forest landscape.

The latest estimate does not suggest that all those gains have disappeared. Instead, it raises concern about the direction of the population after several years of stability. Researchers say continued conservation work will be necessary to keep the population from slipping further.

How can scientists count jaguars hiding in dense forests?

Researchers cannot simply walk through the Atlantic Forest and count every jaguar they encounter. Instead, they rely heavily on motion-activated camera traps positioned throughout the animals’ habitat.

When a jaguar passes a camera, it can trigger photographs or video recordings. Each animal has a distinctive pattern of spots, allowing researchers to identify individuals from their markings.

That makes repeated monitoring possible even when animals are rarely seen directly. Scientists can compare photographs collected over time and then use mathematical models to estimate the wider population.

The 2024 monitoring effort covered more than 570,000 hectares in Argentina and Brazil. Researchers placed 267 camera-trap stations across strategic locations throughout the study area.

Why is the jaguar population still so vulnerable?

The jaguar faces several threats across the remaining forest. Poaching remains a problem, even though hunting the species is illegal and punishable under law in Misiones.

Jaguars can also come into conflict with people living near protected areas. Domestic animals can become targets, creating difficult situations for both rural communities and wildlife.

Roads present another danger as highways cut through forested landscapes. Forest loss and fragmentation can create additional problems by breaking continuous habitat into smaller, disconnected areas.

One of the clearest lessons from the monitoring work is that jaguars need connected forests. Their habitat stretches across Argentina and Brazil, making cooperation between both countries essential.

Researchers have documented individual cats moving across the international boundary. Hendú, a male first identified in Argentina’s Iguazú National Park in 2020, was later recorded in Brazil during 2024.

Kunumi, a female fitted with a satellite collar, crossed the Iguazú River and appeared in areas visited heavily by tourists. Another young male named Perí was born in Brazil before later being photographed in Argentina.

These movements show why protecting one isolated park cannot solve the problem alone. Jaguars need corridors that connect protected forests and give them room to find territory.

Jaguars in the Atlantic Forest: What Has Changed

As the largest big cat in the Americas and the third-largest worldwide, the jaguar (Panthera onca) serves as a vital apex predator across Western Hemisphere ecosystems.Weighing anywhere from 80 to over 300 pounds, these solitary hunters possess an extraordinarily powerful bite capable of piercing armored prey like caimans and heavy turtle shells.Unlike most big cats, jaguars thrive near water and are exceptional swimmers, hunting across diverse landscapes ranging from dense Amazonian rainforests and swampy wetlands like the Pantanal to dry scrublands and coastal mangroves.

Officially classified as Near Threatened on the IUCN Red List, the jaguar currently occupies roughly half of its historic territory, stretching from northern Mexico to northern Argentina. Its global population status presents a stark divide: the massive subpopulation in the Amazon Basin remains relatively stable, holding around 89 percent of all surviving wild individuals. Outside this stronghold, however, nearly all other identified regional subpopulations—including those isolated in Central America, the Brazilian Cerrado, and the Atlantic Forest—are classified as endangered or critically endangered due to deep genetic isolation and intense land conversion.

The species faces persistent pressure from deforestation, habitat fragmentation, retaliatory hunting by livestock ranchers, and an emerging illegal trade in jaguar teeth and bones. In response, multinational conservation efforts are increasingly focused on the Jaguar Corridor Initiative, an ambitious framework aimed at linking isolated reserves across country borders to preserve vital gene flow. Combined with community engagement, improved law enforcement, and livestock protection measures, these connectivity projects offer a realistic path toward securing the long-term survival of the species.