托福口语 Task 4

Today, we're going to talk about a fascinating concept in animal behavior known as 'sensory exploitation.' This occurs when a male animal's courtship signal evolved to exploit a pre-existing sensory bias in the female, even if that bias originally served a completely different purpose. For example, consider the túngara frog. Female túngara frogs are naturally attracted to the 'chuck' sound, which they also use to locate water sources, because the sound mimics raindrops. Males that add a 'chuck' to their call are more successful in attracting females. Another example is the swordtail fish. Females have a natural preference for long, dark objects, likely because they resemble a tasty worm. Male swordtails evolved a long, sword-like extension on their tails, which females find irresistible, even though it makes the males slower and more vulnerable to predators. Thus, sensory exploitation shows that male signals are not just about quality, but about tapping into pre-existing female sensitivities.