How do ectotherms generally respond to temperature variations?

Ectotherms, often referred to as "cold-blooded" animals, primarily rely on external environmental temperatures to regulate their body temperature. Thus, their physiological processes are heavily influenced by the surrounding environment. As the temperature changes in their habitat, ectotherms will naturally experience corresponding changes in their body temperature. This means that when the environment warms up, their body temperature increases; conversely, when the environment cools, their body temperature decreases. This characteristic of ectotherms is essential for their survival, as they do not possess mechanisms to regulate their body temperature internally like endotherms, or "warm-blooded" animals do.

In contrast, while migrating to warmer climates or increasing metabolic rates could be behaviors associated with some animals, they are not defining characteristics of ectothermic responses to temperature changes. Generating internal heat through shivering is also a trait primarily found in endothermic organisms, which actively regulate their body temperature. Therefore, the accurate description of how ectotherms respond to temperature variations revolves around the direct adjustment of their body temperatures in accordance with environmental changes.