What started as a peaceful expedition turned into a jaw-dropping discovery deep in the Amazon rainforest.

A team of scientists from the University of Queensland, invited by the Waorani people, ventured into Ecuador’s remote Baihuaeri Waorani Territory to investigate rumors of the world’s largest anacondas. Led by biologist Professor Bryan Fry, the team spent 10 days exploring river systems—and what they found was extraordinary.

Among the dense jungle and muddy waters, the researchers encountered several massive snakes, including a female measuring 6.3 meters (20.7 feet) long. These northern green anacondas (Eunectes akayima), previously undocumented, may be the largest species of snake alive today.

One shocking encounter—caught while filming Pole to Pole with Will Smith for National Geographic—involved a snake launching itself from the river, revealing the raw power and size of these giants.

Genetic studies revealed that this species diverged from the southern green anaconda nearly 10 million years ago, with a 5.5% genetic difference—more than double the gap between humans and chimpanzees.

But with deforestation and climate change threatening the Amazon, scientists warn that this rare discovery may also be a fragile one. The world’s biggest snake may soon be fighting for survival in a vanishing habitat.