Researchers studying the genetic makeup of various types of anacondas in the Amazon rainforest over a period spanning 20 years have discovered that there are two genetically distinct types of green anaconda — a species previously categorized as a single animal. 

The findings were published in the February edition of the scientific journal Diversity, and Australian biology professor Brian G. Fry also wrote about the findings for independent news site The Conversation. 

"What we were there to do was use the anacondas as an indicator species for what kind of damage is being done by the oil spills that are plaguing the Yasuni in Ecuador, because the oil extraction is absolutely out of control," Fry told Reuters news agency. 

The researchers published video footage showing a colleague from the Netherlands, Freek Vonk, swimming with the giant snake that's over 6 meters (20 feet) long and weighs around 200 kilos (440 pounds). 

Visually identical, genetically very divergent

Their analysis of the animals showed, to the researchers' surprise, that the green anacondas in Ecuador were genetically markedly different from those further south and that the two species began diverging around 10 million years ago. 

"But the really amazing part was, despite this genetic difference, and despite their long period of divergence, the two animals are completely identical" in terms of outward appearance, Fry said. 

Fry described the 5.5% genetic divergence as "an incredible amount of genetic difference, particularly when you put it in the context that we're only 2% different from chimpanzees." 

It was thought that there was only one species of green anaconda, known as Eunectes murinus. Fry and his team propose naming the new type Eunectes akiyama and the northern green anaconda, while dubbing Eunectes murinus the southern green anaconda.

The southern green anaconda can be found in Peru, Bolivia, French Guiana and Brazil — and the northern green anaconda in Ecuador, Colombia, Venezuela, Trinidad, Guyana, Suriname and French Guiana.

Found amid filming for Will Smith documentary

Fry wrote that very little research had previously been done into the genetics of the now five known types of anacondas and that the long-running project was seeking to close that gap. 

"Crucial pieces of the puzzle came from samples we collected on a 2022 expedition to the Bameno region of Baihuaeri Waorani Territory in the Ecuadorean Amazon," he wrote. "We took this trip at the invitation of, and in collaboration with, Waorani leader Penti Baihua. Actor Will Smith also joined the expedition, as part of a series he is filming for National Geographic." 

The researcher said learning of the two species' divergence could have considerable ramifications for conservation efforts. 

"Until now, the two species have been managed as a single entity. But each may have different ecological niches and ranges, and face different threats," he wrote. "Tailored conservation strategies must be devised to safeguard the future of both species."

Anacondas are not venomous and spend much of their time swimming in water, helping explain how they can operate with such huge bodies. They use their powerful and flexible jaws to subdue prey, then crush it with their bodies before eating it.

Fry said the findings showed the importance of genetic analysis of animals in potentially identifying other undiscovered species whose uniqueness might not be noticed otherwise.

Written with material from Reuters.

Edited by: Alex Berry