Scientists shocked to discover new species of green anaconda, the world’s biggest snake

Bryan G. Fry, The University of Queensland

The green anaconda has long been considered one of the Amazon’s most formidable and mysterious animals. Our new research upends scientific understanding of this magnificent creature, revealing it is actually two genetically different species. The surprising finding opens a new chapter in conservation of this top jungle predator.

Green anacondas are the world’s heaviest snakes, and among the longest. Predominantly found in rivers and wetlands in South America, they are renowned for their lightning speed and ability to asphyxiate huge prey then swallow them whole.

My colleagues and I were shocked to discover significant genetic differences between the two anaconda species. Given the reptile is such a large vertebrate, it’s remarkable this difference has slipped under the radar until now.

Conservation strategies for green anacondas must now be reassessed, to help each unique species cope with threats such as climate change, habitat degradation and pollution. The findings also show the urgent need to better understand the diversity of Earth’s animal and plant species before it’s too late.

An impressive apex predator

Historically, four anaconda species have been recognised, including green anacondas (also known as giant anacondas).

Green anacondas are true behemoths of the reptile world. The largest females can grow to more than seven metres long and weigh more than 250 kilograms.

The snakes are well-adapted to a life lived mostly in water. Their nostrils and eyes are on top of their head, so they can see and breathe while the rest of their body is submerged. Anacondas are olive-coloured with large black spots, enabling them to blend in with their surroundings.

The snakes inhabit the lush, intricate waterways of South America’s Amazon and Orinoco basins. They are known for their stealth, patience and surprising agility. The buoyancy of the water supports the animal’s substantial bulk and enables it to move easily and leap out to ambush prey as large as capybaras (giant rodents), caimans (reptiles from the alligator family) and deer.

Green anacondas are not venomous. Instead they take down prey using their large, flexible jaws then crush it with their strong bodies, before swallowing it.

As apex predators, green anacondas are vital to maintaining balance in their ecosystems. This role extends beyond their hunting. Their very presence alters the behaviour of a wide range of other species, influencing where and how they forage, breed and migrate.

Anacondas are highly sensitive to environmental change. Healthy anaconda populations indicate healthy, vibrant ecosystems, with ample food resources and clean water. Declining anaconda numbers may be harbingers of environmental distress. So knowing which anaconda species exist, and monitoring their numbers, is crucial.

To date, there has been little research into genetic differences between anaconda species. Our research aimed to close that knowledge gap.

Untangling anaconda genes

We studied representative samples from all anaconda species throughout their distribution, across nine countries.

Our project spanned almost 20 years. Crucial pieces of the puzzle came from samples we collected on a 2022 expedition to the Bameno region of Baihuaeri Waorani Territory in the Ecuadorian Amazon. 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.

We surveyed anacondas from various locations throughout their ranges in South America. Conditions were difficult. We paddled up muddy rivers and slogged through swamps. The heat was relentless and swarms of insects were omnipresent.

We collected data such as habitat type and location, and rainfall patterns. We also collected tissue and/or blood from each specimen and analysed them back in the lab. This revealed the green anaconda, formerly believed to be a single species, is actually two genetically distinct species.

The first is the known species, Eunectes murinus, which lives in Perú, Bolivia, French Guiana and Brazil. We have given it the common name “southern green anaconda”. The second, newly identified species is Eunectes akayima or “northern green anaconda”, which is found in Ecuador, Colombia, Venezuela, Trinidad, Guyana, Suriname and French Guiana.

We also identified the period in time where the green anaconda diverged into two species: almost 10 million years ago.

The two species of green anaconda look almost identical, and no obvious geographical barrier exists to separate them. But their level of genetic divergence – 5.5% – is staggering. By comparison, the genetic difference between humans and apes is about 2%.

Preserving the web of life

Our research has peeled back a layer of the mystery surrounding green anacondas. This discovery has significant implications for the conservation of these species – particularly for the newly identified northern green anaconda.

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.

Tailored conservation strategies must be devised to safeguard the future of both species. This may include new legal protections and initiatives to protect habitat. It may also involve measures to mitigate the harm caused by climate change, deforestation and pollution — such as devastating effects of oil spills on aquatic habitats.

Our research is also a reminder of the complexities involved in biodiversity conservation. When species go unrecognised, they can slip through the cracks of conservation programs. By incorporating genetic taxonomy into conservation planning, we can better preserve Earth’s intricate web of life – both the species we know today, and those yet to be discovered.

Bryan G. Fry, Professor of Toxicology, School of the Environment, The University of Queensland

This article is republished from The Conversation under a Creative Commons license. Read the original article.

Read More........→February 19, 2024

Scientists Define a Color Never Before Seen by Human Eyes, Called 'Olo'–a Blue-Green of Intense Saturation

Photo by Hamish on Unsplash

An experiment in human photoreceptors allowed scientists to recently define a new color, imperceptible by the human eye, that lies along the blue-green spectrum but is different from the two.

The team, who experimented on themselves and others, hope their findings could one day help improve tools for studying color blindness or lead to new technologies for creating colors in digital imagery.

“Theoretically, novel colors are possible through bypassing the constraints set by the cone spectral sensitivities…” the authors write in their abstract. “In practice, we confirm a partial expansion of colorspace toward that theoretical ideal.”

The team from University of California, Berkeley and the University of Washington used pioneering laser technology which they called “Oz” to “directly control the human eye’s photoreceptor activity via cell-by-cell light delivery.”

Color is generated in our vision through the transmission of light in cells called photoreceptors. Eye tissue contain a series of cones for this task, and the cones are labeled as L, S, or M cones.

In normal color vision, the authors explain, any light that stimulates an M cone cell must also stimulate its neighboring L and/or S cones because the M cone spectral response function lies between that of the L and S cones.

“However, Oz stimulation can by definition target light to only M cones and not L or S, which in principle would send a color signal to the brain that never occurs in natural vision,” they add.

Described as a kind of blue-green with “unprecedented saturation” the new color, which the researchers named “olo” was confirmed as being beyond the normal blue-green spectrum by each participant who saw it, as they needed to add substantial amounts of white for olo to fit somewhere within that spectrum.

“The Oz system represents a new experimental platform in vision science, aiming to control photo receptor activation with great precision,” the study says.

Although the authors are confidant that olo has never been seen before by humans, the spectrum of blue-green has received international attention before as a field of vision discovery.

A groundbreaking study of the Himba people in Namibia conducted in 2005 and published in journal of the American Psychological Association demonstrated that these traditional landowners seemed to perceive various colors as the same because they used the same word for them. A grouping of colors we in the West would separate into pink, red, and orange, is all serandu to them.

That was only half of the cause for fascination with the study. The other half came from the Himba people’s unbelievable sensitivity to the blue-green spectrum, such that they could reliably pick out the fainest differences in green that Western viewers by comparison missed.

This also corresponded with more words for shades of green which Westerners would never bother specifying, and in fact, the Himba had a harder time pointing out that a blue square was different from green squares when shown a chart, but could reliably select the square of a slightly different shade of green to the rest.But then it got even stranger. Further studies in the following years included genetic testing on the Himba, and it showed they possess an increased number of cone cells in their eyes. This higher density of cones enables them to perceive more shades and nuances of color than the average person, according to the lead author of the genetic research. Scientists Define a Color Never Before Seen by Human Eyes, Called 'Olo'–a Blue-Green of Intense Saturation

Read More........→August 13, 2025