托福口语 Task 4

Today, we're going to talk about a fascinating concept in animal behavior called 'behavioral adaptation through environmental cues.' Specifically, I want to focus on how some animals use seasonal changes to time their reproductive cycles. The main point is that animals have evolved to detect subtle environmental signals, like changes in day length or temperature, to ensure their offspring are born when resources are most abundant. Let me give you two examples. First, consider the Arctic fox. In the far north, day length changes dramatically across seasons. As days start to lengthen in late winter, the fox's body responds by increasing hormone production, which triggers mating. This timing ensures that pups are born in early spring, when prey like lemmings are becoming plentiful. Second, think of the desert-dwelling kangaroo rat. It lives in an environment where rainfall is unpredictable. Instead of relying on day length, it monitors soil moisture and plant greenness. After a significant rain, these cues stimulate reproduction, so the young are born when seeds and vegetation are available. Without these cues, the animals might breed at the wrong time and face food scarcity.