Mammalian basal metabolic rate is proportional to body mass2/3.
The relationship between mammalian basal metabolic rate (BMR, ml of O(2) per h) and body mass (M, g) has been the subject of regular investigation for over a century. Typically, the relationship is expressed as an allometric equation of the form BMR = aM(b). The scaling exponent (b) is a point of contention throughout this body of literature, within which arguments for and against geometric (b = 2/3) and quarter-power (b = 3/4) scaling are made and rebutted. Recently, interest in the topic has been revived by published explanations for quarter-power scaling based on fractal nutrient supply networks and four-dimensional biology. Here, a new analysis of the allometry of mammalian BMR that accounts for variation associated with body temperature, digestive state, and phylogeny finds no support for a metabolic scaling exponent of 3/4. Data encompassing five orders of magnitude variation in M and featuring 619 species from 19 mammalian orders show that BMR proportional, variant M(2/3).
White
Craig R
CR
Department of Environmental Biology, University of Adelaide, Adelaide 5005, Australia. craig.white@adelaide.edu.au
Seymour
Roger S
RS
D000704:Analysis of Variance; D000818:Animals; D001481:Basal Metabolism / Q000502:physiology*; D001831:Body Temperature; D001835:Body Weight / Q000502:physiology; D008322:Mammals / Q000378:metabolism*; D010101:Oxygen Consumption / Q000502:physiology; D013045:Species Specificity