托福口语 Task 4

Today we're going to discuss a fascinating concept in animal behavior called 'signal honesty.' In nature, animals often use signals to communicate with each other, but these signals aren't always reliable. Some signals are honest, meaning they accurately reflect the animal's condition, while others can be deceptive. The key question is: why do some signals remain honest? The answer lies in the cost of producing them. If a signal is costly to produce, only animals in good condition can afford to make it, so the signal becomes a reliable indicator of quality. Let me give you two examples. First, consider the peacock's tail. A male peacock grows a large, colorful tail that is extremely heavy and makes it harder to escape predators. Only healthy males with strong immune systems can grow and maintain such a tail. So, the tail honestly signals the male's health and genetic quality to females. Second, think about the begging calls of nestling birds. When baby birds beg for food, they call loudly and vigorously. This behavior is costly because it attracts predators to the nest. Only well-fed, healthy nestlings can afford to beg at high intensity. Weaker nestlings may beg less because they don't have the energy. Thus, the intensity of begging honestly signals the chick's need and health to the parents, who then adjust their feeding accordingly.