Figure 2. Relationship between herbivore body mass (BM) and characteristics of the natural diet that are indicators of diet quality from comparative studies in African mammals.

a) BM and nitrogen concentration in (fore)stomach contents [42] or the measured diet [43]; note that large herbivores (giraffe, rhinos, hippo, elephant) oppose the trend in the smaller species; b) BM (estimated from other sources) and the crude fibre concentration in rumen contents (data on ruminants only) [52] ; c) BM and the proportion of non-stem material in the rumen [42], [53], [91], [133]–[140]; note that browsing ruminants of very small (dikdik), small (duiker, steenbok), intermediate (bongo) and large size (giraffe) show less systematic variation with BM, but their selective inclusion/exclusion will influence the data set; note also that the African buffalo (and also the hippo) do not follow the clear negative trend seen in smaller grazers.