Ectothermal vertebrates regulate their body temperature within definite limits to maintain physiological processes at their optimal levels. Among others, food processing and absorption are strongly temperature-dependent. Deficiency of adequate temperatures limits ectotherms in growth and maintenance. On the other hand, thermoregulatory behavior is costly and should be constrained by many factors. Using artificial thermal gradients (26–44°C), we measured temperature preferences of 10 spiny-tailed agamas (Uromastyx acanthinura) in controlled indoor experiment. Each lizard could choose place in the terrarium before and after feeding. Then, temperature preferences during pre-feeding and post-feeding periods were compared. We found significant increase of preferred temperature after feeding. Detailed view revealed that there is consistent influence of body size: bigger lizards maintained higher temperature during the whole experiment. We hypothesize that bigger potential predation risk on smaller lizards due to their size would force them to choose less optimal conditions.