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Anaconda – the world’s largest snake?

Anaconda – the largest snake in the world?

Anaconda – myths and facts

This snake has stimulated the imagination of many, leading to numerous myths and false images supported by the Hollywood filmmakers. As we know, in every myth lays a kernel of truth, let us try to separate the myths from the truth and present a real view of anaconda. To begin with…

Anaconda (Eunectes)the heaviest snake in the world and a dexterous swimmer.

9 meters (30 ft) of length, 250 kg (550 lb) of weight – Ladies and Gentlemen – behold the Anaconda. The largest snake in the world…

Anaconda (Eunectes)
Anaconda rarely climbs up the trees.


  • Class: Reptilia
  • Order: Squamata
  • Suborder: Serpentes
  • Family: Boas (Boidae)
  • Subfamily: Boinae
  • Genus: Eunectes

We recognize 4 species of anaconda

  • Bolivian anaconda (Eunectes beniensis) – Bolivia
  • Darkly-spotted anaconda (Eunectes deschanauensel) – Brazil, French Guiana
  • Green anaconda (Eunectes murinus) – the Amazon and Orinoco river basins, Colombia, Venezuela, French Guiana, Ecuador, Peru, Bolivia, Trinidad and Tobago, Paraguay
  • Yellow anaconda (Eunectes notaeus) – Argentina, Brazil, Bolivia, Paraguay, Uruguay

You can also come across a giant anaconda – a mythological big snake found in South America. However, it has little in common with the truth, but more on that, a bit further…

As seen above, anaconda belongs to the boas family. Similarly to pythons they are systematized as Boidae, yet the difference between those genera is substantial – anacondas do not lay eggs. Anacondas are viviparous.

What does ‘Eunectes’ mean?

The term Eunectes is derived from Greek and means ‘good swimmer’.

Anaconda (Eunectes)
Yellow anaconda (Eunectes notaeus).

Areas of occurrence

Anacondas inhabit exclusively the South American continent:

  • Argentina
  • Bolivia
  • Brazil
  • Ecuador
  • Peru
  • Paraguay
  • Venezuela
  • Trinidad and Tobago


Anacondas lead an amphibious lifestyle (they rarely climb up the trees due their body mass). They live mostly in aquatic environment and inhabit the tropical rainforests. Anacondas can swim with a velocity reaching 20 km/h (12 mph) and can stay underwater for up to 20 minutes.


The female anaconda gives birth to live offspring, usually between 10 and 50 baby snakes (largest recorded litter contained 100 snakes). Baby anacondas are about 75 cm (2ft 5.5in) long and weigh around 250 grams. Young anacondas are already independent at birth (convenient isn’t it?) and leave their mother just hours after being born. As they are unprotected, they become easy prey for numerous predators. Only a few percent survive adolescence – hence the number of offspring in one litter.

In natural habitat, anacondas reach 30 years of age.

Anaconda (Eunectes)
Female anacondas are much larger than males. Sometimes males are eaten as a snack… 😉

Anaconda – size

Most myths about these snakes consider their size. If you have read the article on the largest flying ‘dinosaur’ – see Quetzalcoatl – it is obvious that finding a largest, heaviest and longest specimen is of the utmost importance for it is a straight road to fame and wealth.

Since the XIX century a significant shrinkage of the anaconda has been observed. Whereas in the early XX century a statement that Anaconda is the world’s largest snake was valid, today we know that this is not the current state of affairs.

Reports appearing in stories and historic sources carry a resemblance to the adventures of Arthur Conan Doyle’s characters in ‘The Lost World’ (after all both take place in South America). These reports claim that snakes measuring 12, 19, 24 meters (39, 62, 79 ft) or even 35 m (115 ft) exist. The problem with all of these stories was always the same – lack of any evidence of the existence of such snakes.

Today we know that the longest wild Anaconda which length was verified was… 521 cm (17ft 1.1in) long and weighed 97.5 kg (214 lb). It is clearly much less than in case of Medusa – the longest reticulated python (7.67 m – 25 ft 2.0 in).

Bigger males or females?

Anacondas’ characteristic feature, much like birds of prey, is that its females are larger than males. Females reach 30 cm in diameter and a meter in circumference in the widest section.

Anaconda (Eunectes)
Anaconda’s skull.

Green anaconda (Eunectes murinus)

Green anaconda, also known as the common anaconda, is the largest species of its genus. This species is particularly to the filmmakers’ liking, although other anacondas are undoubtedly more beautiful.

This snake lives in the Amazon and Orinoco river basins.


  • Length: females: 4 – 4.5 m (13ft 1.5in – 14ft 9in), rarely exceeding 6 m (19ft 8in); longest recorded 7-7.5 m (22ft 12in – 24ft 7in); males: 2.5 – 3 m (8ft 2in – 9ft 10in)
  • Diameter: up to 30 cm (12in) – empty stomach
  • Diameter : up to 1 m (3ft 3.4in)
  • Weight: 60 – 70 kg (132lb – 154lb), rarely exceeding 100 kg (220lb)

The longest green anaconda held in captivity was 6.27 m (20ft 6.9in) long at the moment of its death (Pittsburgh Zoo). At the body length of 5.94 (19ft 5.9in) it weighed 91 kg (201lb). National Geographic’s webpage informs of the size of 6-9 (19ft 8in – 29ft 6in) meters of length and weight reaching 227 kg (500 lb), yet we do not know what is the foundation of such information. Possibly those are only estimated values.

Cases of putting long skins of those snakes on display in museums occurred, the problem is that these skins were noticeably stretched…

Anaconda (Eunectes)
Anaconda reaches 30 cm in diameter and a meter in circumference in its widest section.

Money, money – 50 thousand dollars reward

Some sources claim that the maximum length of these snakes may exceed 9 meters (29ft 6.3in) and their weight may exceed 200 kg (441 lb). The thing is that a reward of 50 thousand dollars for finding an anaconda longer than 9 m (29ft 6.3in) – funded by the Wildlife Conservation Society in the 1920s and still honored – has not yet been claimed… It is striking that throughout almost a century not one person reported to claim the reward.

Anaconda (Eunectes)
Anaconda inhabits the tropical rainforests, rivers and streams.

Hunting and prey

Anaconda hunts for mammals, fish, birds and other reptiles. There are reports of cannibalistic behaviors among these snakes. Usually a larger female eats a smaller male… as a snack after an amorous tête-à-tête.

Anaconda like every other constrictor causes suffocation of its victims wrapping coils of its body around its prey. Tapirs, turtles or even caimans may be its prey. Similarly to other snakes its prey is swallowed whole and digested throughout a few weeks. After a plentiful meal anaconda normally fasts for a lengthy period of time – even several months. In captivity, there was a record time without food lasted 2 years… To think that the Christian Lent is only 40 days long 🙂

Anaconda (Eunectes)
Anaconda face-to-face with a… tortoise. Wonder who is going to be eaten by whom?

Human attacks

Anaconda is large enough to consume a human child. Unfortunately some cases of human encountering an anaconda proved fatal…

As we know, a snake is able to swallow a victim measuring up to 1/4 of the snakes body length, and being of comparable weight.

Anaconda – a titanoboa’s relative

To conclude – it is worth reading an article on the anaconda’s ancestor, the largest snake ever to crawl on the surface of the Earth, able to defeat a T. RexTitanoboa. To satisfy a deeper interest considering the large snakes of the world, we recommend the ranking: The longest snakes Top 10.

Eaten by an anaconda…

In December 2014, Discovery Channel emitted a controversial picture entitled ‘Eaten Alive’, in which Paul Rosolie was to be eaten alive by a huge anaconda… In case you missed the viewing, a material of his final encounter with the anaconda is shown below.

Anaconda (Eunectes)
You win some, you lose some… This time it is the anaconda which turned out to be prey…


Dinosaur Database

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