[Photo] Eunectes murinus, Green Anaconda.
Photograph by LA Dawson http://commons.wikimedia.org/wiki/User:Dawson Date August 27, 2006

The Green Anaconda (Eunectes murinus, from the Greek "ευν??κτη??, eunectes", meaning "good swimmer"), which has been reported at over 10 meters (32.8 feet) in length (although most are considerably smaller). Although shorter than the longest recorded species, the Reticulated Python, it is considerably heavier. In fact, it is the heaviest snake species in existence. It can weigh 250 kg (551 pounds) and have a diameter of more than 30 cm (11.8 inches). Females are larger than males, averaging 22-26 feet and 12-16 feet respectively. These are found mainly in northern South America, in Venezuela, Colombia, Brazil, Ecuador, northern Bolivia, northeast Peru, Guyana, and the Nariva Swamp in Trinidad[1] where they are known as "Huille" (pronounced Wheel). Despite the hold they have on the imagination, very little information was known about the anacondas until 1992 when the first study was made on the field biology of this species in the Venezuelan llanos by Dr. Jesus Rivas.