1 Any member of the genus Eunectes, a group of large, aquatic snakes found in South America. 2  Eunectes murinus, the green anaconda, the largest species, is found east of the Andes in Colombia, Venezuela, the Guianas, Ecuador, Peru, Bolivia, Brazil and Trinidad and Tobago. Eunectes beniensis, the Bolivian anaconda, the most recently defined species, is found in the Departments of Beni and Pando in Bolivia. 2  The giant anaconda is a mythical snake of enormous proportions said to be found in South America.