Ann & Steve Toon / Save the Rhino Trust trackers (l-r) Denso Tjiraso, Martin Nawaseb, Epson Rukuma at Desert Rhino Camp, Wilderness Safaris, Kunene region, Namibia, May 2013

Ann & Steve Toon / Palmwag HQ for conservation body, Save the Rhino Trust, Damaraland, Namibia, Africa, May 2013

Gertrud & Helmut Denzau / Desert monitor (Varanus griseus) basking with mouth open, Badkhyz Reserve, Turkmenistan

Gertrud & Helmut Denzau / Desert monitor (Varanus griseus) smelling the air with its tongue, Badkhyz Reserve, Turkmenistan

Juergen Freund / Juvenile Perentie monitor lizard (Varanus gigantus) walking through desert, South Australia, Australia

Juergen Freund / Juvenile Perentie monitor lizard (Varanus gigantus) on rocks in outback, South Australia, Australia

Daniel Heuclin / Desert monitor (Varanus griseus) in shade of grass, near Chinguetti, Mauritania

Daniel Heuclin / Desert monitor (Varanus griseus) trying to eat a Sand Viper (Cerastes vipera) a venomous species which is biting the Desert monitor, near Chinguetti, Mauritania Controlled conditions

Daniel Heuclin / Desert monitor (Varanus griseus) in shade of grass, near Chinguetti. Mauritania

Daniel Heuclin / Desert monitor (Varanus griseus) in shade of grass, near Chinguetti. Mauritania

Daniel Heuclin / Desert monitor (Varanus griseus) attempting to eat a Sand Viper (Cerastes vipera) a venomous snake which is defending itself by biting the monitor's neck, near Chinguetti, Mauritania

Daniel Heuclin / Desert monitor (Varanus griseus) trying to ingest a Sand Viper (Cerastes vipera) a venomous species which is biting the Desert monitor, near Chinguetti, Mauritania Controlled conditions