托福口语 Task 4

Today, we're going to talk about a fascinating behavior in the animal kingdom called 'mimicry for protection.' Now, mimicry is when one species evolves to look or act like another species to gain an advantage. The main point I want you to grasp is that mimicry can be a highly effective survival strategy, but the specific form it takes depends on the predator's perception. Let me give you two examples. First, consider the harmless milk snake. It has evolved to mimic the colors of the deadly coral snake. Coral snakes have a distinct red-yellow-black pattern, and milk snakes have a similar red-black-yellow pattern. Because predators, like birds, learn to avoid the dangerous coral snake, they also avoid the milk snake. This is called Batesian mimicry. Second, take the example of the viceroy butterfly. For a long time, scientists thought the viceroy was a mimic of the toxic monarch butterfly. However, recent research shows that viceroys are actually toxic themselves, and the monarch is also toxic. Their similar warning colors, orange and black, help both species. Predators that have eaten one will avoid both. This is called Müllerian mimicry, where two unpalatable species share the same warning signal.