托福口语 Task 4

Today, we're going to talk about a fascinating behavior in the animal kingdom called 'mimicry for defense.' Now, mimicry isn't just about looking like a predator—it can also be about looking like something unappetizing or even dangerous to scare off potential threats. The key point is that animals evolve to imitate a model that predators avoid, and this imitation increases their chances of survival. Let me give you two clear examples. First, consider the monarch butterfly. It’s toxic because it feeds on milkweed as a caterpillar, storing toxins in its body. Birds have learned to avoid monarchs. Now, the viceroy butterfly, which is not toxic, has evolved to look almost identical to the monarch. So predators mistake it for the monarch and leave it alone. That's one example. Second, think about the harmless milk snake. It has bands of red, black, and yellow—very similar to the deadly coral snake. Predators, like birds of prey, recognize the coral snake's pattern and avoid it. So the milk snake, even though it's harmless, benefits from this resemblance. In both cases, the mimic survives because predators fear the model.