Evidence against universal metabolic allometry

1 A long-standing theoretical problem in biology is the relation between organism size M and metabolic rate Q. 2 This long history of research into such a basic pattern is due to the particular shape of the relationship: it is generally observed that the relation is well described as Q ∝ Mb where b is most often between 0·5 and 1. 3 Numerous analyses have focused on determining b using interspecific data, in particular to test whether b = 2/3 or b = 3/4. 4 Here a large amount of intraspecific data on fish are analysed, which show that b ≠2/3, b ≠ 3/4, and especially that there is no single, universal value of b.