Swimming beneath the Sahara: The Thermal Biology of Scincus scincus, the Sand-swimming Skink

Abstract

Little is known about the natural history of the sandfish skink (Scincus scincus), despite its range spanning two continents. In deserts across North Africa and the Arabian Peninsula, these lizards spend up to 90% of their day beneath sand and are uniquely adapted to this environment. However, much about the basic biology of this species remains unknown. With this study, we compiled a robust suite of thermal biology parameters to assess within-individual patterns in sandfish skinks. We first quantified thermal preferences and the use of sand horizons to thermoregulate. We monitored individual lizard body temperatures day and night for one week in an environment where they had the ability to select their ideal temperature. Additionally, we quantified the thermal dependence of performance by recording sprinting speed and diving speed, important for prey capture and predator avoidance, across a range of temperatures. Finally we measured the critical thermal minimum and maximum, allowing us to build a complete thermal performance curve. This then allowed us to test the hypothesis that thermal preferences and the optimal temperature for diving and sprinting performance are correlated. Overall, these data provide understanding of how this unique ectotherm survives in the extreme thermal conditions it inhabits