托福口语 Task 4

Today, we're going to talk about a fascinating concept in animal behavior called 'sensory exploitation.' This theory suggests that certain traits or behaviors in animals evolve not because they directly help survival, but because they exploit pre-existing sensory biases in other animals, often for mating purposes. Let me give you two examples. First, consider the male túngara frog. Female frogs are naturally attracted to the 'plop' sound made when something falls into water, because that sound might indicate a predator or a potential food source. Male túngara frogs have evolved to add a 'chuck' to their call, which mimics that 'plop' sound, thereby exploiting the females' existing sensitivity to that noise to attract more mates. Second, think about the guppy fish. Female guppies have a natural preference for orange-colored objects, likely because in their environment, orange fruits fall into the water and are a sign of food. Male guppies with brighter orange spots on their bodies are more attractive to females, even though these spots make them more visible to predators. So, in both cases, the traits evolved not for survival but because they trigger a sensory response that already existed in the opposite sex.