Major C4 grass expansions during the late Miocene in both the Northern and Southern Hemispheres had a major impact on biological communities. We report that the diverse terrestrial fauna of Langebaanweg, South Africa, existed in a local environment that remained C3-dominated during the late Neogene (∼5 Ma). In contrast, other Southern Hemisphere sites at similar latitudes show a clear shift to C4 grasslands well before 5 Ma. Our results are based on stable isotope analyses of enamel carbonate from four artiodactyl and two perissodactyl families from this locality. We also provide insight into the evolution of the current Mediterranean climate system in this part of South Africa.