Which term best describes how reptiles regulate temperature?

Which term best describes how reptiles regulate temperature?

• A. Endothermic
• B. Ectothermic
• C. Homeothermic
• D. Poikilothermic

Answer: (B)

Reptiles regulate their temperature primarily through external heat sources, not by generating their own heat. This is described as ectothermy: their body temperature tends to rise and fall with the environment, and they use behavior—like basking in the sun to warm up or moving to shade to cool down—to manage it. Endothermic animals, such as mammals and birds, generate metabolic heat to stay warm and typically maintain a constant internal temperature (homeothermy), which reptiles do not do. Poikilothermic describes having body temperatures that vary with the surroundings, which is true for reptiles, but the question asks how they regulate temperature, and the mechanism best fitting that description is ectothermic.

Reptiles regulate their temperature primarily through external heat sources, not by generating their own heat. This is described as ectothermy: their body temperature tends to rise and fall with the environment, and they use behavior—like basking in the sun to warm up or moving to shade to cool down—to manage it. Endothermic animals, such as mammals and birds, generate metabolic heat to stay warm and typically maintain a constant internal temperature (homeothermy), which reptiles do not do. Poikilothermic describes having body temperatures that vary with the surroundings, which is true for reptiles, but the question asks how they regulate temperature, and the mechanism best fitting that description is ectothermic.