托福口语 Task 4

Today, we're going to talk about a fascinating concept in animal behavior called 'sensory exploitation.' This idea suggests that in some species, males evolve certain traits not just because females find them attractive, but because these traits exploit pre-existing sensory biases in females. These biases evolved for other reasons, like finding food or avoiding predators. Let me give you two examples. First, consider the swordtail fish. Females of this species naturally prefer longer tails, even though longer tails are not necessarily better for swimming. This preference likely evolved because longer tails make the fish appear larger, which helps females avoid predators. Males exploit this by growing a 'sword' on their tail, which makes them look longer and thus more attractive to females. Second, look at the tungara frog. Females are attracted to the 'whine' part of the male's call, which they use to locate other frogs. Males add extra 'chucks' to the call, which makes it more attractive, even though it also makes them more vulnerable to predators. The females' sensory system is wired to respond to those extra sounds because they resemble sounds of prey.