C-13/C-12 ratios in plants depend on factors like temperature, evaporation or seasonal moisture distribution. Fluctuations of C-13/C-12 in Procavia capensis (hyrax) dung samples from different vegetation zones and various ages over the last 20 000 years indicate variations in the amounts of C4 and CAM, or C3 plants consumed by these herbivores. Potentially they also indicate vegetation changes that may have occurred. C-13/C-12 values for a series of hyrax middens of Late Pleistocene/Holocene age, from a variety of biomes across Southern Africa, show that hyraxes favour mainly C3 plants in their diets but they do incorporate CAM or C4 plants under certain circumstances. Keywords: Hyrax dung deposits, Stable carbon isotope, Physical geography, Geosciences, Vegetation changes.