托福口语 Task 3

In biology, the concept of “behavioral thermoregulation” refers to the deliberate actions animals take to regulate their body temperature by moving to or creating environments with more favorable temperatures. Unlike physiological mechanisms such as shivering or sweating, behavioral thermoregulation involves the animal’s conscious or instinctive choices. This strategy is common among ectotherms, or cold-blooded animals, which rely on external heat sources to maintain optimal body temperatures for activities like digestion, hunting, and escaping predators.

Professor: So, let me give you an example from a study I conducted on desert lizards. These lizards are ectotherms, meaning they can't generate their own body heat. In the early morning, the desert sand is cool, so the lizards bask on sun-warmed rocks to raise their body temperature. This helps them become more active for hunting insects. But by midday, the sand becomes scorching hot—over 50 degrees Celsius. If the lizard stayed on the ground, it would overheat and risk death. So, what does it do? It climbs onto a vertical rock surface and raises its body perpendicular to the sun, minimizing direct exposure. Then, when the sun gets even harsher, it retreats into a shaded crevice or burrow, where the temperature is cooler. At dusk, when the sand cools again, the lizard comes out to feed. Throughout the day, the lizard actively selects microhabitats to keep its body temperature within a safe range, demonstrating behavioral thermoregulation.