托福口语 Task 4

Today we're going to talk about animal communication, specifically how some animals use visual signals in ways that go beyond simple warning or mating displays. A key concept here is 'signal reliability' – how an animal ensures its message is honest and not easily faked. For a signal to be reliable, it often needs to be costly to produce. This is called the 'handicap principle.' Let me give you two examples. First, consider the peacock. The male's elaborate tail is extremely heavy and makes it harder to escape predators. Only a healthy, strong peacock can survive with such a burden. So, when a female sees a large, vibrant tail, she knows the male is genetically fit – the cost guarantees honesty. Second, think of the gazelle 'stotting.' When a gazelle spots a predator like a lion, it doesn't always run away immediately. Instead, it leaps high into the air with stiff legs, repeatedly. This is risky and wastes energy. But it signals to the lion, 'I'm so fast and strong that I can afford to jump around – you won't catch me.' The lion often gives up because it knows the chase will be futile. So, in both cases, the costly nature of the signal is what makes it trustworthy.