Near-Field Sound Detection Some animals are able to use sound to avoid predators. When sound is produced, it creates vibrations in the surrounding air. These vibrations are known as near-field sounds because they originate, or begin, near the sound source. Most animals are unable to detect these kinds of sounds; however, some animals have an ability known as near-field sound detection. This ability allows certain animals to detect vibrations or near-field sounds produced by potential predators. Animals with near-field sound detection abilities have special physical features that allow them to sense an approaching predator and take action to protect themselves.
Now listen to part of a lecture in a biology class.
OK, so let's look at an example of this with insects. Take caterpillars, for example. Some caterpillars have this ability. Now say there’s a caterpillar crawling along oil a branch in a tree， just minding its own business. And then some dangerous insect, like a wasp, flies toward the tree. The caterpillar could be in trouble. The wasp might try to eat the caterpillar. It's a threat. Now, a lot of other animals may not hear the wasp or know that ifs close by. But fortunately for the caterpillar, there are these really tiny hairs on the caterpillar skin, little hairs that stick out into the air around the caterpillar. And When the wasp flies toward the tree, the beating of its wings makes a sound which sends out vibrations or small movements in the air, which make the caterpillars tiny hairs move. So it senses the presence of the wasp. So once the caterpillar realizes something is flying toward it, and it might be a wasp, the caterpillar will just drop off the branch it's been crawling on and fall to a lower branch or to the ground. And This way, the wasp is likely to just fly right by without ever catching the caterpillar. And the caterpillar will be safe.
Explain how the example from the professor's lecture illustrates the concept of near-field sound detection.
Near-field sound detection is an ability that some animals have to detect vibrations or near-field sounds produced by their potential predators when they are approaching. These animals can take actions to protect themselves immediately. In the listening, the professor uses caterpillars as an example. Imagine that a caterpillar is crawling on a branch. Sometimes there can be really dangerous predators like wasps. Perhaps other animals wouldn't sense them, but fortunately, caterpillars have special tiny hairs that stick out from their skin so that they can sense the vibrations made by the wasps when they are beating the wings. Once the caterpillar realizes this, it will drop off the branch and escape as soon as possible to assure its safety.
