托福口语 Task 3

In biology, the concept of “behavioral thermoregulation” refers to the deliberate actions an animal takes to control its body temperature by moving to different environments or adjusting its posture. Unlike physiological mechanisms (like sweating), behavioral thermoregulation is a conscious or instinctive choice that helps an organism maintain an optimal internal temperature for survival. This strategy is common among ectotherms—animals that rely on external heat sources—but can also be observed in endotherms. The key is that the animal actively seeks or avoids specific microclimates.

Professor: So, let me give you a clear example from a desert lizard. In the morning, when the ground is cool, the lizard basks on sun-heated rocks. It flattens its body to absorb maximum heat, raising its temperature quickly. As the midday sun becomes intense, the ground gets too hot—reaching 50 degrees Celsius. If the lizard stayed, it would overheat. So, what does it do? It lifts its body high off the hot sand, using its legs to create a small gap of cooler air beneath, and then it scurries to the shade of a bush. There, it may also change its posture, facing the sun with its head down to reduce surface area exposed. By moving between sunny and shady spots throughout the day, the lizard keeps its body temperature within a safe range, around 37 degrees. This active back-and-forth movement is a perfect case of behavioral thermoregulation.