The common hippopotamus is semiaquatic, inhabiting rivers
The hippopotamus is the type genus of the family Hippopotamidae
The pygmy hippopotamus belongs to a different genus in Hippopotamidae
The suggested subspecies were never widely used or validated by field biologists;
One branch would evolve into cetaceans, possibly beginning about 52 million years ago
Three species of Malagasy hippopotamus became extinct during the Holocene on Madagascar
Three species of Malagasy hippopotamus became extinct during the Holocene on Madagascar,
