托福口语 Task 4

Today, we're going to talk about a fascinating concept in animal behavior called 'sensory exploitation.' This refers to the idea that animals evolve certain traits or behaviors not because they directly help survival, but because they exploit pre-existing sensory biases in other animals—usually for mating purposes. Let me give you two examples. First, consider the túngara frog. Male túngara frogs produce a simple 'whine' call to attract females. However, some males add a 'chuck' at the end. Females naturally have a preference for low-frequency sounds—this is a pre-existing bias that helps them locate larger predators. The extra 'chuck' happens to be low-frequency, so it triggers that bias, making these males more attractive. Second, look at the guppy fish. Female guppies are naturally attracted to orange colors, possibly because orange in their environment signals ripe fruit, a food source. Male guppies in some populations have evolved orange spots on their bodies. These spots aren't useful for camouflage or finding food; they simply exploit the females' existing visual preference for orange. So in both cases, evolution has favored traits that tap into sensory systems that already exist for other reasons.