Morley Read / Tropical flat snake (Siphlophis compressus) climbing on a flowering bromeliad (Aechmea) in the Amazon rainforest, Orellana Province, Ecuador. (non-ex)

Morley Read / Slow motion clip of a Linnaeus' sipo snake (Chironius exoletus) with open mouth, part of threat display, Amazon rainforest, Orellana Province, Ecuador. (non-ex)

Morley Read / Parrot snake (Leptophis ahaetulla) threat display, Amazon rainforest, Orellana Province, Ecuador. (non-ex)

David Tipling / Common European adder (Vipera berus) two males fighting over a female. Holt, North Norfolk, England, UK. April

David Tipling / Common European adder (Vipera berus) two males fighting over a female, Holt, North Norfolk, England, UK. April

David Tipling / Common European adder (Vipera berus) two males fighting over a female, Holt, North Norfolk, England, UK. April.

Daniel Heuclin / Horned viper (Vipera ammodytes) in natural setting, Turkey.

Paul Hobson / Parrot snake (Leptophis ahaetulla) in aggressive pose with mouth open. Costa Rica.

Tony Phelps / Cape cobra (Naja nivea) spreading its hood, retreats into hole, De Hoop Nature Reserve, Western Cape, South Africa, January.

Tony Phelps / Cape cobra (Naja nivea) emerging from a Cape gerbil (Gerbilliscus afra) burrow, hunting and smelling with its tongue, De Hoop Nature Reserve, Western Cape, South Africa, January.

Tony Phelps / Cape cobra (Naja nivea) hunting, chasing a Cape gerbil (Gerbilliscus afra), De Hoop Nature Reserve, Western Cape, South Africa, December.

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