托福口语 Task 4

Today, we're going to talk about a fascinating concept in biology called 'mimicry' — specifically, when animals evolve to look like other, more dangerous species to avoid predators. This is called Batesian mimicry. The key point is that the mimic gains protection because predators learn to avoid the model species, and then generalize that avoidance to the mimic. Let me give you two examples. First, consider the scarlet kingsnake. It has bright red, yellow, and black bands, very similar to the venomous coral snake. Predators like birds avoid the coral snake because of its deadly bite. Once they've learned to avoid the coral snake's pattern, they also avoid the kingsnake, even though it's harmless. Second, there's the hoverfly. It has yellow and black stripes, resembling a wasp. Wasps can sting, so birds avoid them. The hoverfly, which cannot sting, benefits from this resemblance. Birds that have had a bad experience with a wasp will stay away from the hoverfly too. So, in both cases, the harmless species survives better because predators mistake them for dangerous ones.