Body weight exponents of metabolic rate and minimal thermal conductance in burrowing desert rodents

Abstract

Most small burrowing desert rodents have basal metabolic rates (BMR or M) and minimal thermal conductance (C) which are lower than expected. These values are also lower than the values for non-desert species of similar mass. Metabolism–mass and conductance–mass relationships for burrowing desert rodents have been proposed as follows: M = 3·334W−0·95; C = 0·897W−0·499; where M, C, and W are expressed in units of cm3 O2/g/h, cm3 O2/g/h/°C and g, respectively. Combination of high BMR and low C values in very small mammals may compensate in thermoregulation for a high surface–mass ratio. Differences in metabolism–mass and conductance–mass functions for heteromyid, cricetid and murid rodents are discussed.