Fig. 3. (A) The fit of four taxonomic groups to the overall log₁₀L_E–COT trendline: mammals (red), birds (blue), reptiles (gray) and arthropods (yellow). (B) Boxplots of log₁₀COT residuals from the L_E–COT regression for each taxonomic group. *Residuals significantly greater than for mammals (P<0.05, Student's t-test). COT, cost of transport; L_E, effective limb length.