Are lizards classified as ectotherms or endotherms?

Lizards are classified as ectotherms, which means they rely on external sources of heat to regulate their body temperature. Unlike endotherms, which maintain a stable internal body temperature regardless of the environment (such as mammals and birds), ectotherms like lizards absorb heat from their surroundings. This leads them to depend on environmental conditions, such as sunlight or warm surfaces, to achieve the necessary body temperature for their metabolic processes.

Ectothermy allows lizards to conserve energy by reducing their metabolic rate when temperatures drop, making them highly adaptable to varying climates. Additionally, lizards often engage in behaviors like basking in the sun to raise their body temperature or seeking shade to cool down, which underscores their reliance on environmental heat rather than intrinsic heat generation.

Understanding this classification is crucial for recognizing the ecological and physiological adaptations of lizards in their habitats, contrasting with other categories like endotherms, which have mechanisms to generate heat internally.