Most amphibians have minimal barriers to evaporative water loss (EWL) from their skin, with only three families of frogs having some species with either moderate or high cutaneous resistance to water loss. Although the family Bufonidae (toads) is not one of these three, a recent study found moderate resistances to EWL in some populations of Cane Toads (Rhinella marina), but not in others. Three possible explanations for this pattern were suggested: evolution, developmental plasticity, or a physiological process. We measured EWL from three populations of Cane Toads in northern Australia within hours of their capture, including a population from a semi-arid site that had moderate cutaneous resistance in the earlier study. We found no differences in cutaneous resistance among the populations, with all populations having low resistance values of < 2 s/cm. Given the absence of persistently higher resistances at the semi-arid site, we conclude that neither evolution nor developmental plasticity are responsible for the higher values of cutaneous resistance previously reported. Rather, the higher values were most likely the result of an unmeasured temporary physiological response. However, it is not known whether the response is a physiological condition related to artificial conditions (transport, extended captivity, or other human-induced stressors) or a response to environmental stressors present during the first study but absent during this one. This study demonstrates that "field" measurements taken soon after capture can facilitate the interpretation of physiological results in both ecological and evolutionary contexts. Further, it highlights the phylogenetic restrictions that apparently limit the adaptive radiation of cutaneous resistance among non-estivating amphibians.