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

Juergen Freund / Black-headed python (Aspidites melanocephalus) perched on a tree branch overlooking the Australian outback. Queensland, Australia, February

Daniel Heuclin / California kingsnake (Lampropeltis californiae) moving across sand. Sonoran Desert, Arizona, USA. May.

Daniel Heuclin / California kingsnake (Lampropeltis californiae) moving across sand. Sonoran Desert, Arizona, USA. May.

Stephen Dalton / Grass snake (Natrix natrix) moving across the ground, Sussex, UK

Claudio Contreras Koob / Gopher snake (Pituophis catenifer), Santa Margarita Ranch, near Cotulla, Laredo Borderlands, Texas, USA. April.

Claudio Contreras / Texas indigo snake (Drymarchon melanurus erebennus) amongst Vervain (Glandularia sp.) flower, Laredo Borderlands, Texas, USA. April

Pete Oxford / Eastern diamondback rattlesnake (Crotalus adamanteus) on sand dune. Little St Simon's Island, Barrier Islands, Georgia, USA, March.

Juergen Freund / Green tree python (Morelia viridis) coiled around a tree branch. Indonesia, July 2009.

Nature Production / Japanese eels {Aguilla japonica} slithering up waterfall on migration, September, Japan

Nature Production / Japanese eels {Aguilla japonica} 20-30cm in length, slithering up the rocks of a waterfall, Koza River, Wakayama, Japan

Michael & Patricia Fogden / Amethythine Scrub Python (Morelia amethistina) slithering down tree trunk, Australia