Puff adder (Bitis arietans) swallowing a xeric four-striped grass mouse, alternatively called a four-striped grass rat (Rhabdomys pumilio). Puff adder venom is cytotoxic, causing severe pain, swelling, blistering and in many cases severe tissue damage. This viper is found in savannah and grasslands from Morocco and western Arabia throughout Africa, except for the Sahara and rainforest regions. Photographed in the Nossob riverbed of the Kgalagadi Transfrontier Park in Southern Africa.