Species & Evolution

Two hippopotamus species are alive today. The common hippopotamus (Hippopotamus amphibius) is the third-largest land mammal on Earth, found across sub-Saharan Africa wherever permanent fresh water exists. The pygmy hippopotamus (Choeropsis liberiensis) is a separate species entirely — smaller, solitary, forest-dwelling, and Endangered — surviving in the remnant rainforests of West Africa in numbers estimated below 3,000.

This section covers both living species in full, along with the evolutionary history of the hippopotamus family: how hippos are most closely related to whales and dolphins despite appearances, which species have gone extinct in the last 10,000 years, and what the fossil record tells us about how this remarkable lineage developed. For anyone wanting to understand not just what hippos are, but where they came from, this is the place.