Green Anaconda

E. murinus

Last updated: May 13, 2022
Verified by: AZ Animals Staff
© Patrick K. Campbell/Shutterstock.com

Females are often five times longer than males.

Green Anaconda Scientific Classification

Kingdom
Animalia
Phylum
Chordata
Class
Reptilia
Order
Squamata
Family
Boidae
Genus
Eunectes
Scientific Name
E. murinus

Read our Complete Guide to Classification of Animals.

Green Anaconda Conservation Status

Green Anaconda Locations

Green Anaconda Locations

Green Anaconda Facts

Prey
Anything it can fit in its mouth
Main Prey
Capybara, birds, peccaries
Name Of Young
neonate
Group Behavior
  • Solitary except during mating season
Fun Fact
Females are often five times longer than males.
Estimated Population Size
Unknown
Biggest Threat
Humans killing large specimens; juveniles and males preyed upon by larger predators
Most Distinctive Feature
Huge size
Distinctive Feature
Spots
Other Name(s)
Matatoro, water boa, sucuri, yakumama
Gestation Period
6 months
Diet
Omnivore
Lifestyle
  • Diurnal
  • or Nocturnal Depending on Region and Season
Favorite Food
Capybara, birds

Green Anaconda Physical Characteristics

Color
  • Brown
  • Grey
  • Yellow
  • Green
Skin Type
Scales
Lifespan
13-20+ years
Weight
500+ pounds for females
Length
30+ feet for females, males 10-15 feet
Age of Sexual Maturity
Females 3-4 years; Males 1-2 years
Venomous
No
Aggression
High

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The green anaconda is the heaviest snake globally and the species most people refer to when they say “anaconda.”

It’s not venomous, but this giant snake lives in South America and sometimes reaches 30 feet long. It eats caiman and capybara and is big enough to eat deer and goats; some stories have them eating people.

Amazing Facts About Green Anacondas

  • The heaviest anaconda ever recorded was over 500 pounds, and it was 27.5 feet long.
  • The longest may have been 33 feet long, but no one took official measurements.
  • Females do not eat while pregnant and can give birth to upwards of 100 fully independent babies.

Green Anacondas: Where Can You Find Them?

Green anacondas have an extensive range and inhabit areas of Venezuela, Colombia, Ecuador, Brazil, northeast Peru, northern Bolivia, Guyana, and Trinidad. This species moves very slowly on the land due to its size and prefers the water, where it can move quickly and quietly.

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This snake spends most of its time underwater waiting for its latest meal. Then, it stays near the shore, where it can explode outward to attack deer, giant rodents, peccaries, capybaras, tapirs, turtles, birds, dogs, sheep, caiman, and even jaguars. Most prey taken by an anaconda drowns before it dies of cardiac arrest due to constriction. However, smaller specimens sometimes hide in trees and drop down to surprise their prey.

If the snake lives in an area with a dry season, a green anaconda burrows into the mud and seeks out caves with water in which to hide. Otherwise, it prefers flooded forest floors, slow-moving rivers, swamps, and marshland. The green anaconda is a stealthy ambush predator that’s hard to study because it spends most of its time in the water.

The mating season is usually between March and May. The females release a pheromone to attract males, but scientists don’t know how this works. Some believe it may be airborne, and others think it’s a scent trail. Typically, several males find the female and compete for breeding rights, although sometimes the female chooses the male. Mating only happens in the water, and sometimes the female will eat one of the males. However, after mating, she won’t eat until after she gives birth to between 20 and 40 live young, in approximately six months.



Scientific Name of the Green Anaconda

The scientific name Eunectes murinus describes this giant, water-loving snake. Eunectes means “good swimmer,” and murinus means “mousy or mouse-colored.”

Green anacondas go by several names; among these names are sucuri, matatoro, and yakumama.

Green Anaconda Population and Conservation Status

Their current population is unknown. However, green anacondas are heavily harvested for their skins, and large females are frequently killed to prevent attacks. Even with these challenges, they are common throughout their range and seem unaffected by these practices.

Fully grown female anacondas have few natural predators, thanks to their size. However, the males and juveniles do not enjoy that same level of security and must defend themselves against predation.

The IUCN assessed green anacondas in 2014 and found that they weren’t declining at a dangerous rate for the species. The assessors also noted that it is likely in a relatively stable position due to their extensive range and many protected areas. As a result, they’re currently listed as Least Concern.

Identifying Green Anacondas: Appearance and Description

“It is an undisputed fact that anacondas devour cattle and horses, and the general belief in the country is that they are sometimes from sixty to eighty feet long.”

Alfred Russell Wallace, British naturalist and explorer, 1853.

While these snakes are, in a word, huge, they probably don’t reach the 60 to 80 feet that Wallace and other explorers claimed. Female green anacondas regularly reach 16 feet and can reach 30 feet long with a 12-inch diameter. Some believe they get even longer, but scientists haven’t measured those gargantuan snakes yet. Given how difficult they are to observe in nature, it’s certainly possible that we haven’t seen the biggest one yet.

The green anaconda is a nonvenomous constrictor with a mouthful of rear-pointing, razor-sharp teeth. It’s a smooth, shiny snake with a greenish base color and has round or oval spots down its back and on both sides, with a black-spotted yellow belly. The spots along its side have yellow centers.

Its head, like other boas, is blunt; but its eyes and nostrils sit on the top of its head, allowing it to sit just under the surface of the water without being seen. Its body is thick and muscular and sometimes measures 12 inches in diameter. This species is sexually dimorphic, and the females are sometimes five times longer than the males.

Young green anaconda; females of the species may reach 30 feet long as adults.

©Nynke van Holten/Shutterstock.com

Pictures and Videos of Green Anacondas

green anaconda
Green anacondas are aggressive when in captivity.

©Patrick K. Campbell/Shutterstock.com

Where Do Snakes Live
A Green anaconda (Eunectes murinus), which is especially partial to flooded grassland.

©Patrick K. Campbell/Shutterstock.com

green anaconda closeup
Green anacondas’ eyes and nostrils are on top of their head.

©Patrick K. Campbell/Shutterstock.com

This green anaconda may have been near 30 feet, but without actually measuring it, a guess is all we’ll get.
Green anacondas are generally shy, but if you are calm and do not act aggressively sometimes great experiences can happen.

How Dangerous are Green Anacondas?

This snake has a fearsome reputation, and it’s somewhat deserved. In the wild, it can be very aggressive in defending itself, but would usually rather escape. Sometimes, it is rather placid and curious about humans, as in the video above. However, in captivity, the species tends to be more aggressive and apt to bite.

Placid, beautiful experiences with the snake aside, it is exceptionally strong and can easily injure or kill a human. Verified reports of a green anaconda having eaten people are rare, yet the fact that they have been verified indicates the danger level with large specimens. People not trained in handling large snakes should give it some space, and never handle one without help.

Green Anacondas Behavior and Humans

In areas like Florida, where they are becoming more established, human encounters are happening with increasing regularity. Green anacondas were originally introduced to Florida by people who had grown tired of a huge pet snake. Florida Fish and Wildlife advises people who sight one to call a specialized phone number or report it through an app.

People in their native range hunt them for their skins, but most interactions are accidental and harmless. However, locals often blame green anacondas for missing children, dogs, and livestock. Sometimes this is accurate! They will eat anything they can overpower and swallow and scientists have found various species ranging from rats to deer and cattle in their stomachs.

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About the Author

Gail is a musician, author, and artist with more ideas than time. She loves learning about all things in the natural world. Her upcoming book, Pebble Worms and Fast Walkers is filled with all the random bits that kids love! She lives in North Texas with her husband, twin sons, dogs, cat, two red-eared sliders, and two ball pythons.

Green Anaconda FAQs (Frequently Asked Questions) 

How dangerous are green anacondas?

They’re not to be messed with. In the wild, they’re probably going to attempt escape, but in captivity they can be very aggressive.

How do green anacondas hunt?

Primarily, they’re ambush predators. They float just under the water’s surface, only their eyes and nostrils showing.

What do green anacondas eat?

Anything they can overpower. Seriously. They eat fish, peccaries, dogs, cattle, goats, dear, capybara, and caiman. They’ll also eat birds and eggs.

How big was the biggest green anaconda?

The longest one officially recorded was 27.5 feet long, and weighed over 500 pounds.

Thank you for reading! Have some feedback for us? Contact the AZ Animals editorial team.

Sources
  1. Smithsonian National Zoo, Available here: https://nationalzoo.si.edu/animals/green-anaconda
  2. The Ecology of Human-Anaconda Conflict, Available here: https://journals.sagepub.com/doi/full/10.1177/194008291600900105
  3. Rainforest Alliances, Available here: https://www.rainforest-alliance.org/species/green-anaconda/
  4. USGS Nonindigenous Aquatic Species, Available here: https://nas.er.usgs.gov/queries/FactSheet.aspx?SpeciesID=2636
  5. Reptiles of Ecuador, Available here: https://reptilesofecuador.com/eunectes_murinus.html#10

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