Raw data for: Rhinarium cooling and sensitivity to thermal radiation in domestic dogs

The rhinarium of a dog seems to be cold for sensitivity to weak thermal radiation, such as body heat radiation. However, according to De Cock Buning [1], the temperature of the sensor should not matter for the detection of radiating heat. We investigated the relevance of detector temperature for the amount of transferred thermal energy and the contrast in the thermal image by computer modelling, which showed that the detector has to be colder than the detected temperature in order to receive any thermal radiation from the target. In training experiments, we always presented stimuli in pairs, one close to ambient temperature (due to technical reasons 1-2 ⁰C above) and the other one 10-12 ⁰C warmer. The rhinarium temperature in the trained dogs varied, most likely depending on whether they detected both stimuli or just the warmer one alone, which was enough to solve the task. The present data show that dogs cool their rhinaria if they want to detect radiating heat. We furthermore found a cooling mechanism.