Basal metabolic rates in mammals: Taxonomic differences in the allometry of BMR and body mass

Abstract

1. 1. No single equation adequately describes the allometric relation between body mass and BMR for mammals. 2. 2. Least squares regression of log-transformed data for 248 eutherian species results in a line with a slope (−0.30) significantly different from that of Kleiber's line (−0.25). 3. 3. Interordinal comparisons of least squares regressions of log-transformed BMR and mass suggest that the Insectivora have a significantly steeper slope to their allometric relationship than do most other orders, while the non-insectivore orders are statistically homogeneous with respect to slope. 4. 4. With respect to elevation, Edentata have the lowest BMRs; Marsupialia, Primates and Chiroptera are indistinguishable from each other but above the edentates; Primates, Chiroptera, Rodentia, Lagomorpha and Carnivora form the next highest homogeneous grouping; and Artiodactyla have the highest BMRs, significantly greater than all but Lagomorpha and Carnivora. 5. 5. Analysis of intraordinal variation within the Rodentia suggests significant heterogeneity among families in BMR-mass allometry.