Green Anaconda Fact File

Eunectes murinus

Credit: Bernard DUPONT from FRANCE, CC BY-SA 2.0 <>, via Wikimedia Commons








Wild 10 years

Captive 30 years



Deer, Fish, Birds

Conservation Status


Least Concern

Meet the world's heaviest snake!

The green anaconda is the heaviest snake on Earth weighing in at 250kg (550lbs) though it is beaten for the title of longest snake by the reticulated python.

This species is a resident of South America where they live near water in much of the Northern areas of the continent.

They are a carnivore and as a non-venomous species they will seize prey with their mouth and then wrap around it to squeeze it till it stops breeding. They can take prey as large as a deer or tapir though this is rare.

Green anacondas are often the victims of persecution due to fear surrounding their size. Habitat destruction and vehicle strikes are another threat.

Read on to learn more about these radical reptiles.


What does the green anaconda look like?

Green anacondas are infamous as the world’s largest and heaviest variety of snake. They do not hold the claim to being the longest snake though with this title going to the reticulated python.

They have grown to be 8.8m (29ft) long and 250kg (550lbs) in weight. Their diameter may be as much as 30.5cm (12in) around. Males are much smaller than females.

They have olive green colored skin spotted with black blotches. Their narrow head has an orange-yellow stripe running down the side.

Green anacondas have their eyes and nostrils sat high on the head. This allows them to remain hidden in the water but still see and breathe.


What does the green anaconda eat?

Anacondas are a carnivorous species. This one feeds upon anything which it can overpower. This can range from birds, mammals, reptiles and fish through to larger prey like tapirs, capybara, deer and caimans. It is rare that such a large prey item is eaten.

In some cases cannibalism has been observed with females eating smaller males. Scientists suggest that this may be an opportunistic move after birth to meet their energy needs for the long gestation period.

To kill their prey they will constrict them using their muscular body. Often the prey is dragged into the water which is believed to help them maneuver their food into the correct position. Once a large meal has been eaten it may be months before they eat once again. Their teeth curve backwards to help them keep hold on prey.

A green anaconda is capable of opening the mouth to be almost three times the size of its head. This allows them to consume prey larger than one would assume they could.

Much of their food is taken when prey species come to the water to drink.

These animals are considered one of the few snakes capable of eating a human. Despite this reports of them attacking humans are extremely rare.

Green Anaconda

Credit: Mithun.M.Das, CC BY-SA 4.0 <>, via Wikimedia Commons


Where can you find the green anaconda?

South America is the native home of the green anaconda. Here they can be found in Bolivia; Brazil; Colombia; Ecuador; French Guiana; Guyana; Paraguay; Peru; Suriname; Trinidad and Tobago and Venezuela.


What kind of environment does the green anaconda live in?

Green anacondas will make their home in tropical savannas, grasslands and rainforests. They can also be found in swamps and marshes.

They spend much of their time near watercourses including streams, rivers and flooded grassland. Green anacondas show a preference for slow-moving water bodies.

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How does the green anaconda produce its young?

Breeding season takes place from March to May during the dry season. Female green anacodas move around surprisingly little for this time instead waiting for males to approach them. Many males will approach a single female using a scent trail which they lay down to find her.

On occasion up to 12 males may vie for a single female. These males wrap around the female in what is known as a ‘breeding ball.’ They will then all attempt to mate with the female in a process which may take four weeks before one experiences success.

Female green anacondas may eat their partner after mating which provides the energy she needs during her pregnancy.

This species is capable of giving birth through parthenogenesis. This involves the female fertilizing her own eggs thus meaning she does not need to mate with a male.

Six to seven months after mating the young are born live unlike most snakes which lay eggs. An average clutch contains 20 to 40 anacondas but some have included 100. These young develop inside a membrane which they break out of following birth.

They begin life at 70-80cm (27.5-31.5in) long. Following birth they take off and are responsible for looking after themselves. They generally begin by hiding as they are susceptible to predation.

Until sexual maturity at six years of age a green anaconda will grow rapidly. Growth continues after maturity but at a slower pace.


What does the green anaconda do with its day?

Green anacondas are nocturnal. Most of their day is spent in the water. A lot of their time is spent floating with the snout sitting above the water.

In areas where the savanna seasonally floods these snakes will find water or bury themselves in the mud while it is dry. The ones which are buried in the mud enter a period of dormancy.

These animals are able to detect their prey using the tongue which will pick up chemical signals.

Green anacondas are considered solitary and tend to stay alone in their hunting area.

Green Anaconda

Credit: Public Domain

Predators and Threats

What is impacting the survival of the green anaconda?

As adults green anacondas face no natural predators other than humans but juveniles face a number of predators.

When threatened they may burrow in to mud, escape to the water or roll in to a ball. This protects the head and allows them to retain the ability to strike.

Glands around the cloaca of this snake produce a foul smelling musk which is believed to prevent leeches and ticks attaching in this area.

At present the green anaconda is considered locally common in much of its range but their current population trend has not been determined.

The primary threat to the species appears to be persecution due to their large size.

They are experiencing habitat loss within their aquatic habitat and degradation through the construction of hydroelectric dams. Parts of their range are also used for oil drilling.

In some areas green anacondas have been the victim of vehicle strikes.

Some are captured to be turned in to leather and they may also be used for traditional medicines.

Through much of their range this species is protected by law.

Quick facts

Green anacondas are also referred to as water boas or the common anaconda.

Their scientific name “Eunectes” comes from a Greek word for good swimmer.

A group of green anacondas is known as a bed or a knot.

Green anacondas are a member of the boa constrictor family.

The name anaconda comes from a Tamil word "anaikolra" which meant "elephant killer." These animals were referred to as the "bull killer" by Spanish settlers.

Green Anaconda

Credit: Dave Lonsdale, CC BY 2.0 <>, via Wikimedia Commons


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National Geographic. 2020. Green Anaconda. [online] Available at: <> [Accessed 26 April 2020].

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Calderón, M., Ortega, A., Scott, N., Cacciali, P., Nogueira, C. de C., Gagliardi, G., Catenazzi, A., Cisneros-Heredia, D.F., Hoogmoed, M.S., Schargel, W., Rivas, G. & Murphy, J. 2021. Eunectes murinusThe IUCN Red List of Threatened Species 2021: e.T44580041A44580052. Downloaded on 17 September 2021.

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