Nature 430, 772–775 (2004); doi:10.1038/nature02699

Questions have been raised about the methods used and conclusions reached in this Letter1. In revisiting the work, we realized that we did not provide sufficient methodological details regarding the many steps that went into our growth curve analysis, although the main conclusions of the paper were not affected. We regret any misunderstanding that might have resulted. A detailed rationale is available in the Supplementary Methods and Discussion of this Corrigendum and the source data are provided as Supplementary Data. We thank N. Myhrvold for bringing these issues to our attention.

In our reanalysis we found a minor translational mistake affecting the reported growth for Tyrannosaurus, which does not appear to have contributed to Myhrvold’s concerns (details can be found in the Supplementary Methods and Discussion to this Corrigendum.) The correct equation is Mass = (5,649/[1 + e−0.55(Age−16.2)]) + 5. This produces a maximal growth rate of 758 kg yr−1 using points closely bounding the inflection point and 774 kg yr−1 using the instantaneous equation. The reported value was 767 kg yr−1. This slight discrepancy (see the corrected Fig. 2 in the Supplementary Methods and Discussion to this Corrigendum) does not compromise our conclusion that Tyrannosaurus primarily achieved gigantism through evolutionary acceleration.