Recently in Argentina, a giant river otter popped out of the water right next to the canoe containing, of all people, the director of conservation at Rewilding Argentina.

A good omen, one would think, as not only had the charismatic Pteronura brasiliensis not been seen in Argentina since the 1980s, but the river upon which Sebastián Di Martino was floating sat within a park his organization helped create.

"It reared up, so its white chest was visible, which I recognized as the giant river otter," Di Martino told the Guardian. "At this point, your legs go weak and your heart starts beating faster."

Di Martino was kayaking on the Bermejo River in Impenetrable National Park—the legacy of one of the world's great conservationists, Douglas Tompkins, founder of The North Face and Esprit outdoor suppliers, who transferred one of the largest land fortunes on Earth to the governments of Chile and Argentina upon his death.

The otters hadn't been seen on the Bermejo River in over a century, but the waterway is connected to the Paraguayan Pantanal so the simplest explanation is that it swam there, even though it would be a journey of over 1,000 kilometers (600 miles).

Di Martino thinks that since otters live in family groups, the one he saw was simply part of a remnant population that has since gone undetected. It's not a crazy hypothesis, since Impenetrable National Park is 128,000 hectares, or 500 square miles of rivers and woods within Gran Choco Forest, an extremely biodiverse region.

Giant river otters are known as "Wolves of the River," and like the wolf, they are top predators. Their hunting exerts a regulatory influence on the rest of the ecosystem, keeping the links in the riverine world in order. They're also extremely charismatic, trusting, and curious, and can grow 4.5-feet long and weigh more than 60 lbs.

The coincidence of the magical meeting between the riverine mammal and Di Martino is that his organization, Rewilding Argentina, is currently working on a conservation plan to reintroduce giant river otters to the country; to the very park in which he spotted one. The plan also includes reintroductions for the collared peccary, Pampas deer, red and green macaws, and even jaguars.

A good omen, one would think, as not only had the charismatic Pteronura brasiliensis not been seen in Argentina since the 1980s, but the river upon which Sebastián Di Martino was floating sat within a park his organization helped create.

"It reared up, so its white chest was visible, which I recognized as the giant river otter," Di Martino told the Guardian. "At this point, your legs go weak and your heart starts beating faster."

Di Martino was kayaking on the Bermejo River in Impenetrable National Park—the legacy of one of the world's great conservationists, Douglas Tompkins, founder of The North Face and Esprit outdoor suppliers, who transferred one of the largest land fortunes on Earth to the governments of Chile and Argentina upon his death.

The otters hadn't been seen on the Bermejo River in over a century, but the waterway is connected to the Paraguayan Pantanal so the simplest explanation is that it swam there, even though it would be a journey of over 1,000 kilometers (600 miles).

Di Martino thinks that since otters live in family groups, the one he saw was simply part of a remnant population that has since gone undetected. It's not a crazy hypothesis, since Impenetrable National Park is 128,000 hectares, or 500 square miles of rivers and woods within Gran Choco Forest, an extremely biodiverse region.

Giant river otters are known as "Wolves of the River," and like the wolf, they are top predators. Their hunting exerts a regulatory influence on the rest of the ecosystem, keeping the links in the riverine world in order. They're also extremely charismatic, trusting, and curious, and can grow 4.5-feet long and weigh more than 60 lbs.

The coincidence of the magical meeting between the riverine mammal and Di Martino is that his organization, Rewilding Argentina, is currently working on a conservation plan to reintroduce giant river otters to the country; to the very park in which he spotted one. The plan also includes reintroductions for the collared peccary, Pampas deer, red and green macaws, and even jaguars.

It's all part of the late Doug Tompkins and his widow Kris's incredible dedication to the wilds of South America, who through the money from their companies created 13 national parks containing over 5.9 million hectares of pristine land in Chile and Argentina.

The sighting of the otter on a river known for illegal fishing activities is a smashing sign that there is plenty still worth saving in the world right now.

(WATCH the Guardian video of the exciting ‘pop up' moment below.)

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