The aim of this study was to provide insight into how students may use infrared cameras in inquiry-based investigation of animals’ temperature. Upper-secondary students at the vocational Natural Resource Use programme in Sweden were given the open-ended task to design and conduct an investigation of animals’ temperature with the help of an infrared camera. Video data from two groups of students are analysed. One group of students specialise in natural sciences and focused on differences in temperature of horses’ legs. They adopted a focus on the process of thermal regulation in their explanations of differences in temperature, due to e.g. inflammations and limitation of blood flow in cold conditions, and were excited to find alternative explanations when initial predictions were not confirmed. In contrast, a group of students that do not specialise in natural sciences explained differences in ear temperature between rabbits as due to structural characteristics of the individual animals, e.g. differences in size, and had difficulties handling the situation when their predictions were not confirmed. Infrared cameras were found to be useful for inquiry into animal physiology, among students with different levels of science knowledge.