Faecal analysis of diet in free-ranging mammals can provide insight into local habitat conditions by reflecting the resources actually utilized. Here we used stable light isotope analysis of faeces to qualify, as well as quantify, certain aspects of mammal food selection in a recovering,nutrient-poor, savanna habitat in theWaterberg. Stable carbon isotope ratios in faeces reflect proportions of C3-foods (browse) to C4-foods (grass) consumed, whereas stable nitrogen isotope ratios reflect a combination of trophic behaviour,protein intake,and water and nutritional stress. Percentage nitrogen indicates the nutritional quality of the diet, at least in terms of crude protein intake. We used these data to reconstruct and compare the diets of various mammal species from two reserves in the Waterberg: the Welgevonden Private Game Reserve and Zoetfontein Private Game Farm.