Franco Banfi / Close view of a Green anaconda, (Eunectes murinus) underwater, Formoso River, Bonito, Mato Grosso do Sul, Brazil

Francois Savigny / Breeding ball of Anacondas {Eunectes murinus} Venezuela - up to 10 males surround one female

Luciano Candisani / Green Anaconda (Eunectes murinus) female constricting male after copulation, after which she will consume him, Brazil

Nick Garbutt / Yellow Anaconda (Eunectes notaeus) in vegetation at the edge of the Paraguay River, Taiama Reserve, western Pantanal, Brazil, South America.

Franco Banfi / Green anaconda (Eunectes murinus) underwater, flicking tongue, Formoso River, Bonito, Mato Grosso do Sul, Brazil

Franco Banfi / Green anaconda (Eunectes murinus) swimming inFormoso River, Bonito, Mato Grosso do Sul, Brazil

Jeff Rotman / Matses Indian men hold a thick-bodied, 18-foot long Anaconda (Eunectes notaeus) that they killed during a night hunt. Amazon, Peru, November 2005.

Pete Oxford / Anaconda {Eunectes murinus) after ingesting Peccary prey, night, Amazon, Ecuador, South America

Pete Oxford / Anaconda sunbathing {Eunectes murinus} Cerrado habitat, Piaui state, Brazil

Claus Meyer / Green Anaconda (Eunectes murinus) moving through wetland vegetation, Pantanal ecosystem, Brazil

Pete Oxford / Anaconda swimming {Eunectes murinus} River Napo Ecuador Amazon

David Pattyn / Green Anaconda (Eunectes murinus) , Cuyabeno wildlife reserve, Sucumbios, Ecuador, July