Female Horned adder (Bitis caudalis). This venomous viper is found in deserts with sparse vegetation, and in semi-arid scrubland in south-western Africa. Its distinguishing feature is the horn-like scale over each eye, which gives rise to its common name. It is a sit-and wait predator and can burrow into loose sand to ambush its prey of small reptiles and rodents. The venom of this snake is mildly cytotoxic, causing swelling and much pain, accompanied by shock and local necrosis. Photographed in the Dorob national park in the Namib Desert, Namibia.