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``Re-examination of the 3/4-law of Metabolism.''
Journal of Theoretical Biology, 209, 9-27, March 2001.
Abstract:
We examine the scaling law B=cMa which connects organismal resting metabolic rate B with organismal mass M, where a is commonly held to be 3/4. Since simple dimensional analysis suggests a=2/3, we consider this to be a null hypothesis testable by empirical studies. We re-analyze data sets for mammals and birds compiled by Heusner, Bennett and Harvey, Bartels, Hemmingsen, Brody, and Kleiber, and find little evidence for rejecting a=2/3 in favor of a=3/4. For mammals, we find a possible breakdown in scaling for larger masses reflected in a systematic increase in a. We also review theoretical justifications of a=3/4 based on dimensional analysis, nutrient-supply networks, and four-dimensional biology. We find that present theories for a=3/4 require assumptions that render them unconvincing for rejecting the null hypothesis that a=2/3.
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