托福口语 Task 4

Today, we’re going to talk about a fascinating concept in animal behavior called 'sensory exploitation.' This idea suggests that certain traits or behaviors in animals have evolved not because they directly help survival, but because they exploit pre-existing biases in the sensory systems of other animals, particularly for attracting mates. Let me give you two examples to clarify. First, consider the guppy, a small freshwater fish. Female guppies have an innate preference for orange-colored objects—a bias that likely evolved because orange signals food in their environment. Male guppies have capitalized on this by developing bright orange spots on their bodies. When a male displays these spots, he triggers the female’s food-seeking response, making her more likely to approach and mate with him. Second, think about the túngara frog. Female frogs are naturally attracted to low-frequency sounds, which help them locate large pools of water for laying eggs. Male túngara frogs have evolved to produce a 'chuck' call that includes a low-frequency component, mimicking the sound of a large rain pool. This call overstimulates the female’s auditory pathway, making her choose that male over others. So, in both cases, the males are not just showing off fitness; they are hijacking an existing sensory bias to their reproductive advantage.