A lack of scientific attention has left large gaps in understanding the lives and habitats one of Africa’s most iconic megaherbivores, the hippopotamus.

A new database of African hippo (Hippopotamus amphibius) populations across southern Africa has revealed holes in the data which show where hippos are present  with some areas lacking population estimates altogether.

“Without reliable information on where hippos live, and the state of their populations, it is challenging to effectively plan to protect them,” says Hannah Lacy, a PhD researcher at the University of Leeds in the UK.

The species is classified as “vulnerable to extinction” by the International Union for the Conservation of Nature (IUCN) Red List. But differing survey methods and levels of funding across countries and regions have resulted in a lack of consistent monitoring.

“We need a centralised spatial database and coordinated surveys to improve the conservation of common hippos – who are important ecosystem engineers – across southern Africa,” says Lacy.

“Their feeding habits shape vegetation patterns along water courses, and their dung contributes to aquatic food webs, supporting species like fish and invertebrates.

“However, despite their ecological, social, and economic importance, common hippos face numerous threats, primarily from human activities.”

Hippo populations have been hit hard by habitat loss, poaching and conflict with humans over the past century. Crude population estimates vary from 60,000 to 87,000 in southern Africa.

The systematic review, published in the journal Biological Conservation, studied almost 200 records dating from 2003 to 2023 from 9 countries.

“The work provides an update on the distribution of common hippo populations across southern Africa and highlights the extent of population fragmentation and isolation,” says Dr Lochran Traill of the University of Leeds, who supervised the research.

“Hopefully, this information will be useful to conservation decision makers.”