---
title: "What the sources say about the Green Anaconda | AnimalTracks.wiki"
description: "51 claims from the Green Anaconda profile, each beside the words of the source that backs it."
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# What the sources say about the Green Anaconda (*Eunectes murinus*)

> 51 claims from the Green Anaconda profile, each beside the words of the source that backs it. A "..." marks a cut in a quote and [brackets] an insertion.

Profile: [Green Anaconda](https://animaltracks.wiki/animals/green-anaconda/)

## Green anaconda. Smithsonian's National Zoo and Conservation Biology Institute.

https://nationalzoo.si.edu/animals/green-anaconda

| The page says | The source says |
| :--- | :--- |
| Up to 550 pounds of camouflaged ambush predator | can weigh 550 pounds (250 kilograms) |
| with eyes and nostrils on top of its head | Their nose and eyes are located on the top of their heads to help them see and breathe while swimming in the water. |
| that kills with suffocating coils | use their muscular bodies to suffocate the prey before swallowing it whole |
| Fish, birds and small mammals as juveniles; deer, capybaras, caimans, tapirs and large birds as adults | Juveniles tend to eat fish, birds and small mammals. Adults are able to consume much larger animals, including deer, capybara, caimans and large birds. |
| Its eyes and nostrils sit on top of its head, letting a green anaconda "see and breathe while swimming in the water," | Their nose and eyes are located on the top of their heads to help them see and breathe while swimming in the water. |
| Females are considerably larger than males, and can reach 30 feet (9 meters) long, 12 inches (30.5 centimeters) across and 550 pounds (250 kilograms) | Females are considerably larger than males. They can reach lengths of 30 feet (9 meters), diameters of 12 inches (30.5 centimeters) and can weigh 550 pounds (250 kilograms). |
| The average life span in the wild is about 10 years; anacondas live much longer in human care, with some reports of them reaching their late 20s | Their average life span in the wild is about 10 years. However, they live much longer in human care, with some reports of anacondas living into their late 20s. |
| though large prey carries a risk of injury | they are careful to weigh the risk of injury with large prey |
| Juveniles tend to eat fish, birds and small mammals; adults can take much larger animals, including deer, capybaras, caimans, tapirs and large birds | Juveniles tend to eat fish, birds and small mammals. Adults are able to consume much larger animals, including deer, capybara, caimans and large birds. |
| Green anacondas have slow metabolisms, and apart from breeding females, they only need to eat once every few weeks | Green anacondas have slow metabolisms, and with the exception of breeding females, only need to eat once every few weeks. |
| Mating generally runs from March to May, during the dry season | Mating generally occurs from March to May during the dry season. |
| Males form groups of up to 13 around one female, a "breeding ball" in which they compete for access to her, and the mating can last up to a month | Males form groups of up to 13 snakes and mate with one female. They form a “breeding ball,” where the males surround the female and compete for access to her cloaca. The mating can last for up to a month |
| Afterward she may eat one or more of the smaller males, as she will not eat again during the seven-month gestation | the female may consume one of more of the smaller males, as she will not eat again for the seven month gestation period (note: source's own wording is 'one of more', a typo for 'one or more') |
| She gives birth to live young in the water, 20 to 40 at a time, and the largest litter on record was 82 | Females give live birth in the water ... can give birth to 20-40 young ... The largest litter on record was 82 young. |
| Green anacondas are native to the northern regions of South America: most abundant in Colombia's Orinoco basin, Brazil's Amazon basin and Venezuela's flooded Llanos grasslands, and also found in Ecuador, Peru, Bolivia, Guyana, Paraguay, French Guiana and Trinidad | native to the northern regions of South America ... most abundant in the Orinoco basin in Colombia, the Amazon River basin in Brazil, and the flooded Llanos grasslands in Venezuela ... also found in Ecuador, Peru, Bolivia, Guyana, Paraguay, French Guiana, and Trinidad |
| habitat loss, hunting and the international pet trade work against it | habitat loss is a threat to green anacondas ... Green anacondas are also hunted by people ... these snakes are also captured for the international pet trade |
| During the mating season, males form groups of up to 13 around one female, called a breeding ball, in which they compete for access to her. The mating can last for up to a month. | Males form groups of up to 13 snakes and mate with one female. They form a “breeding ball,” where the males surround the female and compete for access to her cloaca. The mating can last for up to a month |
| Slow-moving rivers and streams, flooded Llanos grasslands, and rainforest swamps across the northern regions of South America | native to the northern regions of South America ... the flooded Llanos grasslands in Venezuela ... generally live in tropical rainforests and tend to prefer shallow, slow-moving waters, such as streams, rivers and flooded grasslands |
| Females are the larger sex. They can reach lengths of up to 30 feet (9 meters), a diameter of 12 inches (30.5 centimeters), and weights of up to 550 pounds (250 kilograms). | Females are considerably larger than males. They can reach lengths of 30 feet (9 meters), diameters of 12 inches (30.5 centimeters) and can weigh 550 pounds (250 kilograms). |

## Anaconda. San Diego Zoo Wildlife Alliance.

https://animals.sandiegozoo.org/animals/anaconda

| The page says | The source says |
| :--- | :--- |
| A stretchy, ligament-hinged jaw that swallows prey whole | Jaws attached by stretchy ligaments allow the snake to swallow its prey whole. |
| San Diego Zoo calls South America's green anaconda "the heaviest snake in the world." | South America’s green anaconda is the heaviest snake in the world |
| Its jaws are attached by stretchy ligaments, which let it swallow prey whole | Jaws attached by stretchy ligaments allow the snake to swallow its prey whole. |

## Eunectes murinus (Anaconda, Green Anaconda). Animal Diversity Web, University of Michigan.

https://animaldiversity.org/accounts/Eunectes_murinus/

| The page says | The source says |
| :--- | :--- |
| camouflaged ambush predator | Green anacondas rely on stealth and ambush techniques as they hunt. Their body pattern provides effective camouflage |
| tapirs | feed on large prey ... South American tapirs (Tapirus terrestris) (note: ADW lists the tapir among named large prey items; Smithsonian's list does not name it) |
| death comes from suffocating coils, or just as often, from drowning near water | Since feeding usually takes place near the water, prey are as likely to die from drowning as from constriction. |
| its camouflage leaves a submerged anaconda virtually invisible from a short distance away | Their body pattern provides effective camouflage, allowing a submerged anaconda to be virtually invisible from a short distance away. |
| It grabs hold of prey with needle-sharp, curved teeth, throws coils of muscle around the body, and death follows from respiratory arrest and circulatory failure | restraining their prey using their needle-sharp, curved teeth for a secure grip while killing it by constriction ... Death occurs through respiratory arrest and circulatory failure. |
| Feeding usually happens near water, where prey are as likely to drown as to die from constriction | Since feeding usually takes place near the water, prey are as likely to die from drowning as from constriction. |
| and headfirst | ingests its victim headfirst |
| tapirs | feed on large prey ... South American tapirs (Tapirus terrestris) (note: ADW lists the tapir among named large prey items; Smithsonian's list does not name it) |
| It seizes prey with sharp, curved teeth, then coils around the body; death follows from respiratory arrest and circulatory failure. It usually feeds near water, where prey are just as likely to drown as to die from the squeeze. | restraining their prey using their needle-sharp, curved teeth for a secure grip while killing it by constriction ... Death occurs through respiratory arrest and circulatory failure. Since feeding usually takes place near the water, prey are as likely to die from drowning as from constriction. |
| throws coils of muscle around its prey and kills it by constriction, through respiratory arrest and circulatory failure | restraining their prey using their needle-sharp, curved teeth for a secure grip while killing it by constriction ... Death occurs through respiratory arrest and circulatory failure. (note: vibe.reason (#692/#693)) |

## Eunectes murinus (Linnaeus, 1758). USGS Nonindigenous Aquatic Species Database.

https://nas.er.usgs.gov/queries/FactSheet.aspx?speciesID=2636

| The page says | The source says |
| :--- | :--- |
| The US Geological Survey, citing a 2000 study, reports that breeding females are at least five times the size of breeding males | Breeding females are at least five times the size of breeding males (Rivas 2000). |
| dangerLevel: High | There are few records of attacks on humans, and no well-documented deaths (note: #670: no source records a death, so not Deadly; Smithsonian: 'Reports of anaconda attacks on humans are rare') |

## Shibata et al. (2017). Facultative parthenogenesis validated by DNA analyses in the green anaconda (Eunectes murinus). PLOS ONE.

https://doi.org/10.1371/journal.pone.0189654

| The page says | The source says |
| :--- | :--- |
| A mother without a mate at Ueno Zoo in Tokyo had been kept alone for eight years and two months | a female anaconda isolated from other individuals for eight years and two months at Ueno Zoo, Japan. |
| Ueno Zoo in Tokyo | brought to Ueno Zoo, Tokyo, Japan |
| when she died of pneumonia in 2015 | on November 8, 2015, she died of pneumonia. |
| Her autopsy found two almost fully developed but dead female offspring | Autopsy revealed two developed fetuses ... Both fetuses were almost fully developed but dead ... Examination of gonads by dissection confirmed both to be female. |
| at all 16 informative DNA markers they carried only her alleles and no paternal ones | we analyzed 18 microsatellite markers of which 16 were informative. We observed only maternal alleles and no paternal alleles for all 16 markers. |
| The researchers call it the first case of parthenogenesis in Eunectes validated by DNA analysis | This is the first case of parthenogenesis in Eunectes to be validated by DNA analysis |
| A female caught in Guyana | was caught in Guyana and brought to Ueno Zoo, Tokyo, Japan |
| lived alone at a Tokyo zoo for over eight years | a female anaconda isolated from other individuals for eight years and two months at Ueno Zoo, Japan. (note: eight years and two months; Tokyo from 'brought to Ueno Zoo, Tokyo, Japan') |
| When she died, she was carrying two female young | on November 8, 2015, she died of pneumonia. Autopsy revealed two developed fetuses ... Both fetuses were almost fully developed but dead ... Examination of gonads by dissection confirmed both to be female. |
| whose DNA, at 16 markers, showed no sign of a father | we analyzed 18 microsatellite markers of which 16 were informative. We observed only maternal alleles and no paternal alleles for all 16 markers. |
| which the researchers say is the first DNA-confirmed case in the anaconda genus | This is the first case of parthenogenesis in Eunectes to be validated by DNA analysis |

## Rivas et al. (2024). Description of the Northern Green Anaconda (Eunectes akayima sp. nov. Serpentes; Boidae): What Is in a Name? Diversity.

https://doi.org/10.3390/d16070418

| The page says | The source says |
| :--- | :--- |
| In 2024 Rivas and colleagues named the northern green anaconda, Eunectes akayima, as a separate species, saying the two separated about 10 million years ago | we previously documented the existence of two distinct species, Eunectes akayima sp. nov. and Eunectes murinus (Linnaeus, 1758), that separated approximately 10 million years ago (note: 2024 is the reference's own year; the title is 'Description of the Northern Green Anaconda (Eunectes akayima sp. nov.)') |
| and differ notably in how much bigger females grow than males | supported by a notable difference in sexual size dimorphism (SSD) intensity between the two species |
| the describers' later paper says it rectifies earlier oversights in that description | This paper also rectifies earlier oversights in the description of the new species |

## Vásquez-Restrepo, Alfonso-Rojas & Palacios-Aguilar (2024). On the validity of the recently described northern green anaconda Eunectes akayima (Squamata, Serpentes). Bionomina.

https://doi.org/10.11646/bionomina.37.1.1

| The page says | The source says |
| :--- | :--- |
| Other researchers argued that the original description broke the International Code of Zoological Nomenclature and sank the new name as a synonym | the article in question violates fundamental aspects of the International Code of Zoological Nomenclature ... leading to the synonymizing of the recently described species |

## Calderón et al. (2021). Eunectes murinus. The IUCN Red List of Threatened Species 2021: e.T44580041A44580052.

https://doi.org/10.2305/iucn.uk.2021-2.rlts.t44580041a44580052.en

| The page says | The source says |
| :--- | :--- |
| The IUCN lists Eunectes murinus as Least Concern | IUCN Red List category: Least Concern (LC). (note: category read through GBIF's copy of the Red List; iucnredlist.org refuses scripts) |

## Rivas (2023). What can studying anacondas tell us about Titanoboa cerrejonensis? Exploring the life of an extinct giant snake using an extant pretty big snake. The Herpetological Journal.

https://doi.org/10.33256/33.3.6875

| The page says | The source says |
| :--- | :--- |
| weightKg: 22.5 | Mass (NP) 22496.4 14699.4 54000 4700 104 (note: task #739; mean mass of 104 non-pregnant adult females, 22,496 g, from 823 Llanos anacondas caught 1992 to 2014 (Table 1, masses in grams), rounded to 22.5 kg. Medium class (10 to 100 kg). Males in the same table average 5,678.6 g (Light), and the whole sample 11,437.1 g (Medium)) |