The Green Anaconda (Eunectes murinus) is the heavyweight champion of the snake world: a silent, semi-aquatic giant that glides through the slow rivers and flooded grasslands of tropical South America. Here are twelve genuinely remarkable facts that explain why this constrictor fascinates scientists and wildlife lovers alike. For the full picture, see our Green Anaconda species guide.
The headline facts
1. It is the heaviest snake on Earth
No other snake outweighs a big Green Anaconda. Large females can approach 100 kg, and exceptional specimens have been reported far heavier, making bulk, not length, this snake's claim to fame.
2. Females are the giants
Green Anacondas show striking reverse sexual size dimorphism: females routinely exceed 5 metres while males average around 3 metres. The largest individuals you read about are almost always female.
3. It kills without venom
The Green Anaconda is non-venomous. It ambushes prey, throws coils around it, and tightens with every exhalation until circulation stops, then swallows the animal whole.
4. Its eyes sit on top of its head
Eyes and nostrils are set high on the skull, so the snake can lie almost fully submerged while watching the bank, a perfect design for a water ambush predator.
Life in the water
5. Water carries its weight
On land this giant can barely haul its own bulk, so it spends most of its life half-submerged, letting buoyancy do the heavy lifting.
6. It gives birth to live young in water
Anacondas are ovoviviparous: females carry developing young internally for six to seven months and deliver live babies in the water, with roughly 20 to 40 per litter and occasionally many more.
7. Newborns are already huge and on their own
Each snakelet is born about 70 to 80 cm long and fends for itself immediately. There is no parental care.
8. It can fast for weeks
After a large meal such as a capybara or caiman, a Green Anaconda may not need to eat again for weeks, digesting slowly while it rests.
Surprises and conservation
9. It was split into two species in 2024
In February 2024, genetic analysis showed northern populations differ from southern ones by roughly 5.5 percent in their DNA. The northern lineage was named Eunectes akayima, leaving E. murinus as the southern Green Anaconda.
10. Courtship can form a breeding ball
Several smaller males may coil around a single giant female at once, a writhing knot known as a breeding ball.
11. It is an apex wetland predator
Across its range it tops the food web, taking fish, birds, deer, caimans and capybara, signalling a healthy, intact wetland.
12. Trade is monitored under CITES
Demand for its patterned skin and the exotic pet trade is why all anacondas sit on CITES Appendix II. Keeping their wetlands intact is the real key to their future. Protecting these habitats is quiet, partner-led work that a small gift toward habitat protection can help sustain.
Read the full Green Anaconda wildlife guide for the facts, IUCN status and conservation context — or donate to WARN to help fund the local partners protecting this species.
