Bruno D'Amicis / Sand viper (Cerastes vipera) sidewinding on sand dunes. Grand Erg Oriental, Kebili Governorate. Tunisia.

Alex Hyde / Adder (Vipera berus) basking amongst bracken fronds. Peak District National Park, Derbyshire, UK. April.

Daniel Heuclin / Western diamondback rattlesnake (Crotalus atrox) tasting air, in habitat, Arizona, USA, October. Controlled conditions

Chris Mattison / Sidewinder (Crotalus cerstastes) in sand dunes, Anza-Borrego Desert State Park, California, USA, May.

Juergen Freund / Box jellyfish {Chironex sp.} in mangroves, split level, Australia