Sharon Heald / Hippopotamus (Hippopotamus amphibius) charging, Chobe National Park, Botswana, July.

Enrique Lopez-Tapia / Hippopotamus (Hippopotamus amphibius) charging against boat on Lake Chamo. Nechisar National Park. Ethiopia, November 2014

Ole Jorgen Liodden / Hippopotamus (Hippopotamus amphibius) rearing head out of water, creating spray, Lake Naivasha, Kenya.

Hiroya Minakuchi / Hippopotamus (Hippopotamus amphibius) calves, Okavango Delta, Botswana

Ammonite / Group of sub-adult African lions (Panthera leo) chasing and jumping on a mother Hippopotamus (Hippopotamus amphibius) and her calf, footage taken at night using infrared camera technology, Masai Mara,...

Ammonite / Sub-adult African lioness (Panthera leo) chasing and jumping onto the back of a Hippopotamus (Hippopotamus amphibius), footage taken at night using infrared camera technology, Masai Mara, Kenya.

Vincent Grafhorst / Hippopotamus (Hippopotamus amphibius) bull marking territory by flicking dung, Chobe National Park, Botswana

Vincent Grafhorst / Hippopotamus (Hippopotamus amphibius) bull charging in territorial display, Botswana

Vincent Grafhorst / Hippopotamus (Hippopotamus amphibius) bull charging in territorial display, Botswana

Vincent Grafhorst / Hippopotamus (Hippopotamus amphibius) in territorial display, Botswana

Vincent Grafhorst / Hippopotamus (Hippopotamus amphibius), Khwai River, Botswana

Vincent Grafhorst / Hippopotamus (Hippopotamus amphibius) spraying water from nostrils, Khwai River, Botswana