How do lizards regulate their body temperature?

Lizards are ectothermic animals, meaning they rely on external heat sources rather than internal metabolic processes to regulate their body temperature. While often called "cold-blooded," this is a misnomer; when active, a lizard’s blood can be as warm as or warmer than that of mammals.12

Lizards achieve thermoregulation primarily through behavioral strategies. To reach their "preferred temperature"—typically between 28 and 38 °C (82 to 100 °F)—they move between sun and shade, adjust their body orientation to maximize or minimize exposure to solar radiation, and seek out warm surfaces.12

This behavioral control is essential because their physiological performance, including hunting and escaping predators, is optimal only within a specific temperature range. However, thermoregulation involves trade-offs; time spent basking or seeking shelter is time taken away from feeding and reproduction, and exposure to sunlight can increase the risk of predation. Ultimately, a lizard's operating temperature is determined by a combination of its evolutionary history, immediate environmental conditions, and the costs associated with these behavioral choices.12