These are found mainly in northern South America, in Venezuela, Colombia, Brazil, Ecuador, northern Bolivia, northeast Peru, Guyana, and the Nariva Swamp in Trinidad where they are known as 'Huille' (pronounced Wheel). Females are larger than males, averaging 22-26 feet and 12-16 feet respectively.

It can weigh 250 kg (551 pounds) and have a diameter of more than 30 cm (11.8 inches). In fact, it is the heaviest snake species in existence. Although shorter than the longest recorded species, the Reticulated Python, it is considerably heavier. The Green Anaconda ( Eunectes murinus, from the Greek 'ευνήκτης, eunectes', meaning 'good swimmer'), which has been reported at over 10 meters (32.8 feet) in length (although most are considerably smaller).It is unclear how the name originated so far from the snake's native habitat it is likely due to its vague similarity to the large Asian pythons. There are two possible origins for the word 'anaconda': It is perhaps an alteration of the Sinhalese word 'henakanday', meaning 'whip snake', or alternatively, the Tamil word 'anaikondran', which means 'elephant killer', as early Spanish settlers in South America referred to the anaconda as 'matatoro', or 'bull killer'. The Yellow Anaconda can be found as far south as Argentina. Anacondas (local names: Jibóia and Sucuri) are four species of aquatic boa inhabiting the swamps and rivers of the dense forests of tropical South America.

Anaconda largest ever found