Methods: External temperature loggers provide an accurate estimate of core body temperature in the lizard Pogona vitticeps.

Continuous reliable measurements of body temperature are an integral part of physiological and behavioural studies on ectotherms, but often involve invasive surgeries for intracoelomic placement of data loggers. To validate the use of external data loggers, eleven bearded dragons (Pogona vitticeps) were instrumented with three temperature loggers (Ibutton DS1921G) each. One logger was coated with silicone and implanted intraperitoneally during anaesthesia. Following a period of recuperation, a custom-made harness with a logger on both the dorsal and ventral surface was placed around the chest, and the relationships of external and internal temperatures were compared. There was an excellent correlation between the average temperature recorded by the two external loggers and the temperature measured by the implanted logger (Pearson's Correlation: = 0.97 ± 0.03), indicating that the two external temperature loggers provide reliable measures of body temperature in Pogona vitticeps. We propose this simple technique as an alternative to internal loggers to avoid invasive procedures and improve animal welfare.