托福口语 Task 4

Today we're going to discuss a fascinating concept in biology called 'mimicry'. Specifically, I want to focus on a type of mimicry where a harmless species imitates a dangerous one to avoid predators. This is known as Batesian mimicry. The main point is that this imitation provides a survival advantage because predators learn to avoid the dangerous species and, consequently, also avoid the harmless look-alike. Let me give you two examples. The first is the scarlet king snake. It has red, yellow, and black bands, very similar to the venomous coral snake. Predators that have learned to avoid the coral snake will also avoid the king snake, even though it's harmless. The second example involves the hoverfly. Hoverflies have black and yellow stripes, resembling bees or wasps. Birds that have had a painful experience with a stinging insect will steer clear of hoverflies, giving them protection even though they can't sting.