TOEFL Speaking Task 3

In biology, the term "behavioral thermoregulation" refers to the deliberate actions an animal takes to control its body temperature by moving to different environments or changing its posture. Unlike physiological mechanisms such as sweating or shivering, behavioral thermoregulation relies on the animal's ability to sense temperature gradients and respond accordingly. This strategy is common among ectotherms, or cold-blooded animals, which cannot generate their own heat. By selecting warmer or cooler microhabitats, they can maintain optimal body temperatures for essential activities like foraging, digestion, and escaping predators.

Professor: Let's take the desert lizard as an example. In the early morning, the ground is cool, so the lizard lies flat on a sun-warmed rock, spreading its body to absorb heat—this raises its temperature quickly. As the day gets hotter, the rock becomes scorching, so the lizard lifts its body high off the ground, using only its toes to touch the hot surface, reducing contact area to avoid overheating. By midday, when temperatures peak, the lizard retreats into a shady burrow or under a bush, where it stays until the afternoon. When it needs to hunt, it emerges briefly but returns to shade if its body gets too warm. These movements—choosing sunny spots, adjusting posture, and seeking shade—are all behavioral choices that keep its body temperature within a safe range.