9809961 Dearing A fundamental goal in the study of the ecology of mammalian herbivores has been to identify the physiological factors that limit dietary specialization. Although plant secondary compounds have played a paramount role in the generation of diet selection hypotheses of mammalian herbivores and detoxification capability is often proposed as a mechanism determining diet breadth, our understanding of how herbivores detoxify secondary compounds is quite limited. To generate diet selection models with more predictive power and to understand the ecological distributions of herbivorous mammals, we first need to improve our knowledge of the mammalian detoxification system. The objective of the proposed research is to identify and quantify the mechanisms that specialist and generalist herbivores use to detoxify plant secondary compounds by testing the following 3 hypotheses: by producing detoxification metabolites that are less acidic than those produced by generalists; by generating the same acid-load during detoxification as generalists, however, eliminating hydrogen ions (H+) produced in this process through an entirely different route than generalists; and by having a greater capacity to buffer urine than generalists.
