托福口语 Task 4

Today, we're going to talk about how animals use camouflage not just to hide from predators, but also to communicate with each other. This is called 'signal camouflage.' The main idea is that some animals have evolved to send signals that are only visible to their own species, while remaining invisible to predators. Let me give you two examples. First, consider the mantis shrimp. It has bright, colorful spots on its body that are only visible in ultraviolet light. Predators like fish cannot see UV light, so the shrimp appears plain to them. However, other mantis shrimps can see these UV patterns, and they use them to signal aggression or readiness to mate. Second, take the peacock spider. Males have a brightly colored abdomen that they flash during courtship dances. But this flash is only visible to other spiders because the colors are in a range that bird predators cannot perceive. The spider uses this to attract females without drawing attention from birds. So, in both cases, the animals use signals that are tuned to their own receivers, avoiding detection by others.