托福口语 Task 4

Today we're going to talk about a phenomenon in animal behavior called 'sensory exploitation.' This is when a male animal evolves a trait that appeals to a pre-existing sensory bias in females, even though the trait doesn't necessarily indicate the male's quality. The key is that the female already has a preference for certain stimuli because they help her in other contexts, like finding food. Let me give you two examples. First, consider the swordtail fish. Females naturally prefer longer tails, probably because they associate longer extensions with larger bodies, which might mean more food or safety. Males evolved a sword-like extension on their tails to exploit this bias. Even though the sword makes swimming less efficient, females are more attracted to males with longer swords. Second, think about the water mite. Females are attracted to vibrations that mimic the movements of their prey, like small crustaceans. Males have evolved to produce similar vibrations during courtship, tricking the female into approaching, which then allows mating to occur. In both cases, the male's trait exploits a pre-existing sensory preference.