TOEFL Speaking Task 3

In biology, the term 'behavioral thermoregulation' refers to the deliberate actions an animal takes to regulate its body temperature. Unlike physiological mechanisms such as sweating or shivering, behavioral thermoregulation involves the animal's choices—like moving to a different location, changing posture, or altering activity patterns—to either gain or lose heat. This behavior is crucial for maintaining an optimal internal temperature for survival and daily functions.

Professor: Let me give you a clear example from the desert. The desert iguana, a lizard found in the American Southwest, relies heavily on behavioral thermoregulation. In the morning, when the ground is cool, the iguana basks in the sun on a rock, flattening its body to absorb maximum heat. As the day heats up, the ground can get scorching—over 40 degrees Celsius. To avoid overheating, the iguana climbs onto a shady bush or burrows into the sand, where the temperature is cooler. It also alters its posture: it lifts its body off the hot sand and holds its tail up to increase air circulation. By moving between sun and shade and adjusting its position, the iguana keeps its body temperature within a safe range, allowing it to remain active and hunt for insects.