TOEFL Speaking Task 3

In biology, the concept of 'behavioral thermoregulation' refers to the deliberate actions an animal takes to regulate its body temperature by moving to different environments. Unlike physiological responses such as shivering or sweating, behavioral thermoregulation involves conscious choices that exploit environmental temperature variations. This strategy is crucial for ectotherms, or cold-blooded animals, which rely on external heat sources to maintain optimal body temperatures for activities like hunting, digestion, and escaping predators. By selecting warmer or cooler microhabitats, these animals can effectively manage their thermal needs without expending metabolic energy.

Professor: Let me give you a clear example from a desert lizard species. These lizards are active during the day, but the desert floor can get extremely hot. In the morning, when it's cooler, the lizard basks on sun-exposed rocks to absorb heat and raise its body temperature, allowing it to move quickly to catch insects. However, as the day progresses and the ground temperature soars above 50 degrees Celsius, being on the open sand would be deadly. So, the lizard engages in a behavior called 'stilt-walking'—it lifts its body high off the hot surface and quickly runs to the shade of a bush or a rock crevice. In the shade, it presses its body flat against the cooler soil to lose heat. By moving between sunny and shaded areas throughout the day, the lizard keeps its body temperature within a safe range, allowing it to forage and avoid overheating.