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

Colin Varndell / Grass snake (Natrix natrix) Dorset, UK May

Matthew Maran / Grass snake (Natrix natrix) flicking tongue, Hampstead Heath, London, England, UK, August.

Luis Quinta / Grass snake (Natrix natrix) juvenile playing dead, Alvao, Portugal, April.

Luis Quinta / Grass snake (Natrix natrix) swimming in river, Olo, Alvao, Portugal, June.

Claudio Contreras / Checkered garter snake (Thamnophis marcianus) Laredo Borderlands, Texas, USA. April

Juergen Freund / Banded sea kraits (Laticauda colubrina) around the roots of mangrove tree, split level. Mali Island, Macuata Province, Fiji, South Pacific.

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

Danny Green / Grass Snake (Natrix natrix) on lily pad, reflected in water. Leicestershire, UK, October.

Sandesh Kadur / Large scaled pit viper (Trimeresurus macrolepis) head profile, water droplet below, Western Ghats, Southern India