“It was a huge surprise,” said Sebastian Di Martino, director of conservation at Fundacion Rewilding Argentina. “I was incredulous. An incredible feeling of so much happiness. I didn’t know if I should try to follow it or rush back to our station to tell the others.”
The cause of the excitement was the sighting, last week, of a wild giant river otter – an animal feared extinct in the country due to habitat loss and hunting – on the Bermejo River in Impenetrable national park, in north-east Argentina’s Chaco province. The last sighting of a giant otter in the wild in Argentina was in the 1980s. On the Bermejo, none have been seen for more than a century.
Di Martino captured the otter on his phone while kayaking. “It reared up, so its white chest was visible, which I recognised as the giant river otter [Pteronura brasiliensis]. At this point, your legs go weak and your heart starts beating faster.”
There are two possible explanations for the otter’s return. “The closest known populations of giant otter, which is endangered globally, are in the Paraguayan Pantanal, which could connect with this river from a distance of over 1,000km. That’s the simplest explanation,” said Di Martino. “The other possibility is that there’s a remnant population of the species in Argentina that’s gone undetected. These animals live in family groups, and this was a solitary individual, which we think came from a group.”
Impenetrable national park was created in 2014 with the help of Rewilding Argentina and Tompkins Conservation, the organisation set up by Kristine Tompkins and her late husband, Doug, to restore wild areas of Chile and Argentina using money from their companies, The North Face, Esprit and Patagonia. Tompkins Conservation has helped protect 5.9m hectares (14.5m acres) in South America’s southern cone.
Working with governments and public and private partners, the organisation has helped create 13 national parks, including Corcovado, Pumalin, Yendegaia, Kawesqar and Patagonia in Chile and Monte Leon and Ibera in Argentina. Impenetrable’s 128,000 hectares (316,000 acres) of native forest and waterways protect remarkable biodiversity in a largely intact section of Gran Chaco forest, one of the world’s most endangered ecosystems. Last year, a lone jaguar, thought to be extinct in the park, was discovered and has since sired cubs.
Otters have a vital role to play in balancing nature. “Giant river otters, as top predators, exert a regulatory influence in the aquatic ecosystem,” said Di Martino. “It’s a regulator of fish populations, which contributes to the health of aquatic ecosystems. It’s a spectacular animal, and it’s enormous; it can be 1.8 metres long. Adults weigh over 30kg. They’re trusting and curious. To share the environment with them is marvellous.”
The otters are so important that, long before this sighting, there were plans to reintroduce them. Rewilding Argentina has been working to bring back giant otters since 2018, concentrating their efforts in Argentina’s Ibera wetlands. Coco and Alondra, a mating pair from Denmark and Hungary, are currently in a pre-release pen there, waiting to enter their vast new home.