Markle and Kozak (2018) determined the mean critical thermal maximum (CTM) and mean acclimation ability of 16 species of Desmognathus and eastern Plethodon in order to determine how acclimation ability relates to geographic range size. All had comparable CTM, from 31.7 to 33.1 celsius but varied substantially in acclimation ability. They measured standard metabolic rates at three different temperatures and conducted a phylogenetically informed analysis. Wider ranging salamanders display greater acclimation ability than those with smaller geographic ranges. The authors suggest that this greater physiological advantage may have been an important factor in the expansion of range sizes and is likely to provide greater protection from extinction.