Anacondas are four species of aquatic boa inhabiting the swamps and rivers of the dense forests of tropical South America. The Yellow Anaconda can be found as far south as Argentina. There are two possible origins for the word 'anaconda.' It is perhaps an alteration of the Sinhalese word henakandaya, meaning 'whip snake', or alternatively, the Tamil word anaikondran, which means 'elephant killer'.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. Local names for the anaconda in South America include the Spanish term matatoro, meaning 'bull killer', and the Native American terms sucuri, yakumama, and jibóia. Anacondas as members of the boa family are sometimes called water boas. The Latin name for Anaconda is Eunectes.
Species
Bolivian Anaconda, Eunectes beniensis Dark-spotted Anaconda, Eunectes deschauenseei Green Anaconda, Eunectes murinus Yellow Anaconda, Eunectes notaeus
Giant Anacondas
There is some debate about the maximum size of anacondas, and there have been unverified claims of enormous snakes alleged to be as long as 30-45m (98.4-147.6ft). According to Lee Krystek, a 1944 BC petroleum expedition in Colombia claimed to have measured an 63.8m (209.3ft) specimen, but this claim is not regarded as reliable; perhaps a more credible report came from scientist Vincent Roth, who claimed to have shot and killed a 10.3m (34ft) anaconda in Guyana. There are some reports from early European explorers of the South American jungles seeing giant anacondas up to 18.2m (60ft) long, and some of the native peoples have reported seeing anacondas up to 15.2m (50ft) long., but these reports remain unverified. Another claim of an extraordinary size anaconda was made by adventurer Percy Fawcett. During his 1906 expedition, Fawcett wrote that he had shot an anaconda that measured some 18.9m (62 ft) from nose to tail. Once published, Fawcett’s account was widely ridiculed. Decades later, Belgian zoologist Bernard Heuvelmans came to Fawcett's defence, arguing that Fawcett's writing was generally honest and reliable. Historian Mike Dash writes of claims of still larger anacondas, alleged to be as long as 30-45m (100-150ft) -- some of the sightings supported with photos (although those photos lack scale). Dash notes that if a 50-60 ft anaconda strains credulity, then a 150ft long specimen is generally regarded as an outright impossibility. It should be noted that the Wildlife Conservation Society has, since the early 20th century, offered a large cash reward (currently worth $50,000 USD) for live delivery of any snake of 30 feet or more in length. The prize has never been claimed. Also, in a study of 1000 wild anacondas in Brazil, the largest captured was 17 feet long