Insights into the thermal ecology, physiology, and behavior of a threatened ectothermic specialist from a warming and drying ecoregion.

Increased heat and drought from Anthropogenic climate change will challenge the adaptive capacity of species, underscoring the need to understand thermal ecology - how organisms behaviorally and physiologically respond to temperature. We used noninvasive infrared thermography (IRT) to examine the thermal ecology of threatened narrow-headed gartersnakes (Thamnophis rufipunctatus) in a conservation breeding program at the Arizona Center of Nature Conservation/Phoenix Zoo. From 718 microhabitat and 124 individual measurements, hierarchical models identified extrinsic and intrinsic factors influencing microhabitat usage, body temperature (Tb), and behavior. Gartersnakes exhibited regional heterothermy, with tails cooler than head and trunk segments. The Tb of T. rufipunctatus was shaped by perch temperature, perch-air temperature, and whether snakes were visibly exposed or hidden. We documented microhabitat aggregations (≥2 gartersnakes) in ca. 40% of observations, which was best predicted by Tb. Thamnophis rufipunctatus appeared to favor cavity-bearing microhabitats, consistent with wild populations. This first application of IRT to snakes in semi-natural environments, and for T. rufipunctatus specifically, provides novel insights to guide more effective field surveillance and conservation management, while demonstrating the broader value of IRT and collaborative ex situ studies for wildlife conservation.