托福口语 Task 4

Today we're going to talk about a fascinating phenomenon in animal behavior known as 'behavioral thermoregulation.' This is when animals control their body temperature not just by physiological means, but by actively changing their behavior. This is especially important for ectotherms, or cold-blooded animals, which rely on external heat sources to regulate their temperature. Let me give you two examples. First, consider the desert iguana. In the early morning, it basks in the sun to warm up. But when the sun gets too intense at midday, it seeks shade under rocks or burrows into the sand to avoid overheating. This way, it keeps its body temperature within a safe range. Second, think of fish in a lake. Some species, like the bluegill sunfish, will move to warmer shallow waters in spring to speed up their metabolism and growth. But in summer, when shallow waters become too warm and oxygen-poor, they move to deeper, cooler areas. So, by choosing where to be, these animals effectively manage their body temperature,