Thermal ecology and thermal landscape of Sauromalus varius

Dataset shows data on the thermal ecology and thermal landscape of the piebald chuckwalla, Sauromalus varius, an herbivorous reptile living on a hot desert island in one of the warmest areas in the world. Data was collected during the warmest period of the year (July 2023). We recorded field body temperature (Tbfield), voluntary thermal limits (the voluntary maximum body temperature), the onset of thermal stress responses (e.g., panting), and critical maximum temperature (CTmax) at which righting response was lost.

We also determined thermal landscape available to the iguanas on the island. Temperature dataloggers registered temperature every 30 min during six days in the hottest month of the year. Temperature was determined for air temperature (at 150 cm above the substrate) and in the sun (30 cm above the substrate), and for microhabitats available to the iguana: substrate temperature in the sun and shade, under plants, under rocks, and in caves.

Methods
Data on the thermal requirements of the piebald iguana Sauromalus varius during the hottest time of the year and its thermal landscape on the island San Esteban, Sonora, Mexico.

During July 2023 thermal requirements of 15 piebald iguanas, Sauromalus varius, were determined through tests on the island San Esteban, Sonora, Mexico. We obtained field body temperature (measured immediately after capture), maximum voluntary body temperature (at which the iguana sought shade), and maximum critical temperature (at which the iguana lost the righting response). Further, we registered the temperature at the onset of gaping (evaporative heat loss), production of feces, and spasms in the head muscles, signals of thermal stress. Also, time to reach these temperatures was recorded.

In July 2023, 32 dataloggers registered temperatures in microclimates on the island San Esteban, Sonora, Mexico. Dataloggers registered temperature every 30 min over 5 days. Data was obtained from air temperature (at 150 cm above surface; 2 dataloggers), temperature in the sun (30 cm above surface; 3 dataloggers), substrate temperature in the sun (2 dataloggers) and in the shade (2 dataloggers), temperature in the shade of plants without leaves (7 dataloggers) and plants with leaves (6 dataloggers), temperature below rocks (5 dataloggers), and temperature in caves (4 dataloggers).