The structure of the thermal landscape determined behavioural and physiological responses to simulated predation risk

Although predators can deter an animal from regulating its body temperature by basking or shuttling, this response to predation should depend on the spatial distribution of thermal resources. By simulating predation risk, we showed that movement, thermoregulation and corticosterone of male lizards (Sceloporus jarrovi) depended on the spatial distribution of shade. Simulated risk caused lizards to move less, thermoregulate worse and circulate more corticosterone than they did without risk. However, a patchier distribution of shade enabled lizards to move more, thermoregulate better and circulate less corticosterone when exposed to a simulated predator. In the absence of simulated risk, lizards in patchier environments moved less, thermoregulated better and circulated less corticosterone, indicating the distribution of shade also affected the energetic cost of thermoregulation. This study provides the first test of a spatial theory of thermoregulation under the perceived risk of predation. Read the free Plain Language Summary for this article on the Journal blog.