Abstract
Seventy‐five percent of Madagascar is treeless C 4 ‐grassland adapted to human‐lit fire, which likely succeeded pre‐human mosaics of forest, ericoids, grassy‐woodlands and some smaller treeless‐grasslands. In support of pre‐settlement Malagasy grasslands having evolved with many grassland specialist faunal elements, Bond et al. (2022) cite “considerable overlap” in African and Malagasy hippo diets, and suggest time‐scale hampered mammal radiation into treeless‐grasslands. We find, however, that faunal elements referenced are predominantly habitat generalists (not grassland specialists), that African and Malagasy hippos occupy significantly different feeding‐niches, and that despite shared Miocene timeframes, Malagasy non‐arboreal mammals remained forest‐adapted whilst species that share ancestry with them on the African mainland radiated into open habitats.