TOEFL Speaking Task 3

In biology, the concept of 'behavioral thermoregulation' refers to the deliberate actions an animal takes to control its body temperature within an optimal range. Unlike physiological responses such as shivering or sweating, behavioral thermoregulation involves changing the animal’s position, posture, or activity level to exploit or avoid environmental heat sources. This strategy is common among ectothermic animals, which rely on external heat to regulate their internal temperature. By moving between sun and shade, altering their orientation to the sun, or adjusting their activity times, these animals can maintain a stable body temperature for essential functions like foraging and digestion.

Professor: Let me give you a concrete example from a desert lizard species. In the early morning, after a cool night, the lizard’s body is cold, so it emerges from its burrow and basks on a sunlit rock. It flattens its body and turns its back toward the sun to maximize heat absorption. Once its body warms up to the optimal temperature, around 35 degrees Celsius, it must avoid overheating. So, it moves into the shade or burrows under the sand, where it’s cooler. If it still needs to search for insects, it does so in short bursts, running between patches of shade. During the hottest part of the day, it stays in a cool burrow, emerging again in late afternoon when the sun is less intense. This active movement between microhabitats allows the lizard to keep its body temperature stable enough to hunt and digest food.