Malagasy hippopotamuses were first discovered in the mid-19th century by Alfred Grandidier, who unearthed nearly 50 individual hippos from a dried-up swamp at Ambolisaka near Lake Ihotry,[2][3] a few miles from the Mozambique Channel.

[4][5] It may have descended from full-sized hippos who shrunk due to insular dwarfism, similar to many Mediterranean island hippos, such as with the Cretan dwarf hippopotamus or the Cyprus dwarf hippopotamus.

[1] Hippopotamus lemerlei and contemporary Aldabrachelys tortoises were the dominant grazers in Madagascar.

[6] Although there have been no remains dating to within the last thousand years, the hippopotamus has been surprisingly common in Malagasy oral legends.

In different regions of Madagascar, stories were recorded of the mangarsahoc, the tsy-aomby-aomby, the omby-rano, and the laloumena, all animals that resembled hippopotamuses.