Tony Heald / Hippopotamus {Hippopotamus amphibius} territorial defense at water edge, Chobe national park, Botswana.

Ann & Steve Toon / African elephants (Loxodonta africana) herd silhouetted at sunset. Chobe National Park, Botswana.

Tony Heald / African wild dog (Lycaon pictus) portrait. Chobe National Park Botswana. Digitally enhanced sepia image.

Paul Souders/ Worldfoto / Black Heron (Egretta ardesiaca) canopy hunting, Chobe River, Chobe National Park, Botswana

Tony Heald / African elephant (Loxodonta africana) feeding on grasses, Chobe River, Chobe National Park, Botswana. May.

Ann & Steve Toon / Sable (Hippotragus niger), Chobe National Park, Botswana, June

Christophe Courteau / African elephants (Loxodonta africana) swimming across Chobe River, trunks raised above surface for breathing, Chobe National Park, border between Botswana and Namibia.

Neil Aldridge / African fish eagle (Haliaeetus vocifer) standing on the banks of the Chobe River, Chobe National Park, Botswana.

Neil Aldridge / Portrait of an African darter (Anhinga rufa) on the Chobe River, Chobe National Park, Botswana.

Neil Aldridge / Yellow-billed stork (Mycteria ibis) catching a young barbel or catfish in the shallows of the Chobe River, Chobe National Park, Botswana.

Neil Aldridge / Yellow-billed oxpecker (Buphagus africanus) perched on the back of an African buffalo (Syncerus caffer) on the banks of the Chobe River, Chobe National Park, Botswana.

Neil Aldridge / Pied kingfisher (Ceryle rudis) erupts from the water after an unsuccessful dive into the Chobe River, Chobe National Park, Botswana.