托福口语 Task 4

Today we're going to talk about a fascinating concept in animal behavior called 'sensory exploitation.' This occurs when a male animal evolves a trait that exploits a pre-existing sensory bias in the female, making him more attractive to her. The key is that the female's preference exists before the male's trait evolves. Let me give you two classic examples. First, consider the swordtail fish. Female swordtails have a natural preference for longer tails, even in species where males don't have long tails. When a sword-like extension appeared on the tail of some male fish, it triggered this existing preference, making those males more likely to be chosen. Second, think about the tungara frog. Female frogs are attracted to the 'whine' part of a male's call because it resembles a sound they naturally associate with food. Some males added an extra 'chuck' at the end of their whine. This chuck exploits the female's heightened sensitivity to certain frequencies, making those males more successful in mating. So, in both cases, the male's trait didn't create the female's preference; it simply took advantage of what was already there.