RATE OF BASAL-METABOLISM OF GRAZING RODENTS FROM DIFFERENT HABITATS

Scaling of basal rate of metabolism (BMR) to body mass was studied in grazing rodents inhabiting different environments of Chile. Observations support previous general predictions for scaling of BMR in small grazing mammals (high scaling parameters and cost of endothermy at small body sizes). A species-specific analysis of the mass-independent basal rate, suggests that BMR varies with the design features of the organisms and with biotic and abiotic environmental factors (e.g., food quality, habitat characteristics), even within trophic groups. In general, these factors seem not to be independent.