Environmental temperatures are a major constraint on ectotherm abundance, influencing their distribution and natural history. Comparing thermal tolerances with environmental temperatures is a simple way to estimate thermal constraints on species distributions. We investigate the potential effects of behavioral thermal tolerance (i. e. Voluntary Thermal Maximum, VT Max) on anuran local (habitat) and regional distribution patterns and associated behavioral responses. We tested for differences in Voluntary Thermal Maximum (VT Max) of two sympatric frog species of the genus Physalaemus in the Cerrado. We mapped the difference between VT Max and maximum daily temperature (VT Max-ET Max) and compared the abundance in open and non-open habitats for both species. Physalaemus nattereri had a significantly higher VT Max than P. cuvieri. For P. nattereri, the model including only period of day was chosen as the best to explain variation in the VT Max while for P. cuvieri, the null model was the best model. At the regional scale, VTMax-ET Max values were significantly different between species, with P. nattereri mostly found in localities with maximum temperatures below its VT Max and P. cuvieri showing the reverse pattern. Regarding habitat use, P. cuvieri was in general more abundant in open than in non-open habitats, whereas P. nattereri was similarly abundant in these habitats. This difference seems to reflect their distribution patterns: P. cuvieri is more abundant in open and warmer habitats and occurs mostly in warmer areas in relation to its VT Max , whereas P. nattereri tends to be abundant in both open and non-open (and cooler) areas and occurs mostly in cooler areas regarding its VT Max. Our study indicates that differences in behavioral thermal tolerance may be important in shaping local and regional distribution patterns. Furthermore, small-scale habitat use might reveal a link between behavioral thermal tolerance and natural history strategies.

Amphibians and reptiles are ectothermic animals and therefore depend on environmental temperatures to maintain their physiological functions.Despite being poorly documented, data on thermal behavioral thresholds to avoid overheating in their habitats are essential to improve the understanding of their thermal ecology and physiology. Here we provide a data set of 312 individual voluntary thermal maximum (VT Max ) values, the maximum

Ectotherms depend on temperature to maintain their physiological functions and through behavioral changes, they can avoid overheating in their habitats. The voluntary thermal maximum (VTMax) represents the maximum temperature tolerated by individuals before actively moving to a colder place. However, if and how VTMax might change after capture and in captivity remains understudied. We investigate if measurements taken in captivity are a good proxy for thermal tolerance of wild individuals. As thermal history has been shown to affect behavioral response and physiological parameters, herein we hypothesized that VTMax of the neotropical viper Bothrops pauloensis varies throughout the captivity period. We measured the VTMax of individuals immediately after capture and in three trials during a short‐term period in captivity. Measurements were done by recording their body temperature at which they exited a heating box experimental setup. In contrast to our hypothesis, the VTMax was not significantly affected by time in captivity but there was interindividual variation. There were also no significant differences between field and captivity measurements, in spite of the small effect size. Our results indicate that the VTMax of this snake population is not affected by a short‐term captivity period. Furthermore, an invariant VTMax might indicate low phenotypic plasticity, as individuals do not appear to adjust their tolerance to short‐term exposure to higher temperatures and potential vulnerability to threats such as global warming. We expect that our results can contribute to understanding the effect of captivity on thermal tolerance in neotropical squamates, allowing for insights into their thermal physiology and ecology.

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