Visualizing thermoregulation (endothermy vs. ectothermy) in animals can be challenging for students in undergraduate biology courses. Data-driven, hands-on laboratory activities can enhance student learning while reinforcing application of the scientific method. This article describes a visual-learning, inquiry-based activity that can be applied to introductory high school and college biology laboratories with the use of easily accessible technology (a smartphone and an inexpensive thermal camera attachment). Students generate hypotheses and qualitatively observe real-time thermal images of live endothermic and ectothermic animals. This activity is effective in engaging students by allowing them to visualize thermoregulation and body temperature. We provide suggestions for modifying the activity to further investigate animal behavior related to temperature regulation.