A giant river otter swimming through the waters of a South American wetland.
The Return of an Apex Predator
After a four-decade absence, the giant river otter has officially returned to the wetlands of Argentina. The country recently achieved a global conservation milestone by reintroducing a family of four otters to the Gran Parque Iberá in Corrientes.
This marks the world’s first successful attempt to return the endangered species to a habitat where it had been completely wiped out. The last confirmed sighting of a giant otter in Argentina was in 1986.
Meet the New Wetland Residents
The reintroduced family features Nima, a female brought in from the Madrid Zoo, and Coco, a male transferred from Denmark’s Givskud Zoo. They are joined by their two pups, which were born directly in the Iberá wetlands in November 2024.
Gran Parque Iberá offers an ideal sanctuary for the growing family. The protected reserve spans over 756,000 hectares of rich wetlands, providing abundant prey and a striking absence of significant natural threats.
A Biological Heavyweight
The giant river otter (Pteronura brasiliensis) is an apex predator endemic to South America. It is the largest member of the weasel family, capable of reaching lengths of 1.8 meters and weighing more than 30 kilograms.
Recognizable by their dense brown fur and a distinct yellowish-white throat patch, these highly social mammals typically live in groups of five to ten individuals. They spend the vast majority of their lives in the water, relying on long whiskers to detect fish and dense, waterproof fur to stay dry.
During the 1950s and 1960s, the species was hunted relentlessly for its valuable pelt, pushing it to the brink of extinction. Today, remaining populations face ongoing threats from habitat loss, poaching, and exposure to canine distemper.
Restoring the Ecosystem
“The giant otter is the main aquatic predator of these wetlands,” explained Sebastián Di Martino, conservation director of Rewilding Argentina. He noted that their fish-heavy diet plays a critical role in keeping the local water systems and broader ecosystems healthy.
Local authorities are also optimistic about the economic impact. Gustavo Valdés, governor of Corrientes, highlighted the recovery effort’s dual benefits.
“The giant otter not only comes to occupy its rightful place in the aquatic ecosystem, but it will attract more tourists eager to observe it,” Valdés said. “Iberá is consolidating itself as an example in species recovery, nature tourism, and genuine local development.”
Rewilding Argentina is not stopping here. The organization plans to execute further releases in the Esteros del Iberá and the Chaco region, aiming to restore connectivity between isolated otter populations across South America.
