Reports of giant anacondas date back as far as pre-columbian times, playing a role in indigenous cultures of the Amazon Basin. European colonization of South America reported sightings of giant anacondas. The size of the largest anacondas has been the subject of debate ever since among cryptozoologists and zoologists.
Anacondas have been verified to grow to sizes of 5.5 metres (18.0 ft) and 100 kilograms (220.5 lb). In particular, the green or common anaconda is the heaviest and largest among all extant snakes in terms of robustness, and it is also the second-longest.
While the longest reputably-measured and confirmed anaconda was about 5.5 metres (18.0 ft) long, extreme lengths far in excess of this have been reported for this species, without verification. Some claims describe anacondas ranging from 8 to 12 metres (26.2 to 39.4 ft), although these remain unverified.
Giant anacondas play a role in the oral traditions of indigenous cultures as guardians of the river and its fauna, as well as bringers of storms and rain. They are said to form and guard Matupás, floating vegetation islands which have only recently in 2015 been discovered to be valuable components of the Amazon's ecosystems .
The first recorded sightings of giant anacondas were from the time of the colonization of South America, when early European explorers entered the dense jungles and claimed to have seen giant snakes measuring up to 18 metres (59.1 ft) long. Natives also reported seeing anacondas upwards of 10 to 18 metres (32.8 to 59.1 ft). Anacondas above 5 metres (16.4 ft) in length are rare. The Wildlife Conservation Society has, since the early 20th century, offered a large cash reward for live delivery of any snake of 30 feet (9.1 m) or more in length, but the prize has never been claimed, despite the numerous sightings of giant anacondas. In a survey of 780 wild anacondas in Venezuela, the largest captured was 17 feet (5.2 m) long. A specimen measured in 1944 exceeded this size when a petroleum expedition in Colombia claimed to have measured an anaconda which was 11.4 metres (37.4 ft) in length, but its claim has never been proven.
Scientist Vincent Roth claimed to have shot and killed a 10.3 metres (33.8 ft) specimen, but like most other claims, it lacks sound evidence. Another claim of a large anaconda was made by British adventurer Percy Fawcett. Following his 1906 survey of the Bolivia/Brazil border, Fawcett wrote that he had shot an anaconda that measured some 19 metres (62.3 ft) from nose to tail. Once published, Fawcett’s account was ridiculed. Decades later, Belgian cryptozoologist Bernard Heuvelmans came to Fawcett's defence, arguing that Fawcett's writing was generally honest and reliable. Historian Mike Dash writes of claims of even larger anacondas, alleged to be as long as 45 metres (147.6 ft), with some of the sightings supported with photos (although the photos lack scale). Dash noted if reports of a 18 metres (59.1 ft) anaconda strains credulity, then a 120 feet (36.6 m) long specimen would be an impossibility.
Anacondas have been featured in many stories around Latin America, such as those written by Uruguayan writer Horacio Quiroga, who also founded a group of Argentine and Uruguayan intellectuals around 1920 called the Anaconda Association. He also published a book named Anaconda around 1921. Willard Price, famous author of many children's books in the mid 20th Century, wrote about a 10 meter Anaconda in "Amazon Adventure".
An anaconda was featured in an episode of Lost Tapes called "Megaconda".
The anaconda is one of the snakes that can be captured and eaten in Metal Gear Solid 3: Snake Eater.
- Rivas, Jesús Antonio (2000). The life history of the green anaconda (Eunectes murinus), with emphasis on its reproductive Biology (PDF) (Ph.D. thesis). University of Tennessee. pp. 74–80, 111. Retrieved 2016-02-04.
- Soomro, A. 2001. "Eunectes murinus" (On-line), Animal Diversity Web. Accessed January 10, 2008 at http://animaldiversity.ummz.umich.edu/site/accounts/information/Eunectes_murinus.html
- Weldon, Kevin (1993). Encyclopedia of Animals: Mammals, Birds, Reptiles, Amphibians. Sydney, Australia: Reader's Digest Association Inc. p. 489. ISBN 1875137491.
- Murphy, J. C.; Henderson, R. W. (1997), Tales of Giant Snakes: A Historical Natural History of Anacondas and Pythons, Krieger Pub. Cous., ISBN 0-89464-995-7.
- de Freitas CT, Shepard GH Jr, Piedade MTF (2015) The Floating Forest: Traditional Knowledge and Use of Matupá Vegetation Islands by Riverine Peoples of the Central Amazon. PLoS ONE 10(4): e0122542. https://doi.org/10.1371/journal.pone.0122542
- Extreme Science: Which is the Biggest Snake?. Accessed January 10, 2008.
- The Search for the $50,000 Snake. Archived 2009-10-31.
- Krystek, Lee, The Unmuseum: Big Snakes, retrieved January 10, 2008
- Justice, Aaron, Cryptozoology: Sucuriju Gigante, archived from the original on 2008-01-15, retrieved January 10, 2008
- Section Bernard Heuvelmans. Accessed January 10, 2008.
- Dash, Mike (2000), Borderlands: The Ultimate Exploration of the Unknown, Overlook Press, ISBN 0-87951-724-7