In the sunny mornings of São Paulo's countryside, the Teiú (Salvator merianae), the largest lizard in Brazil, can often be seen basking on rocks or logs, soaking up the sun's warmth to charge its internal 'battery,' as being ectothermic, it relies heavily on environmental temperatures for thermal regulation. Recent research conducted in Jaboticabal by scientists from the Agrarian and Veterinary Sciences Faculty of UNESP, supported by FAPESP, has unveiled a unique metabolic mechanism that enables the Teiú to increase its body temperature notably during the breeding season. This phenomenon occurs even when the lizards are hidden in cold, dark burrows, defying biological assumptions that only birds and mammals can generate such consistent internal heat. This revelation not only highlights the adaptability and complexity of the Teiú but also prompts a reassessment of thermal regulation mechanisms among reptiles. By understanding how the Teiú can effectively heat itself during crucial periods of reproduction, researchers provide valuable insights into the evolutionary biology of this species and potentially similar ectothermic organisms. Such findings can have broader implications for understanding reptilian biology, reproductive strategies, and the adaptation of species to changing environments.