托福听力

🎧 听力原文

Narrator: Listen to part of a lecture in a biology class. Professor: Today we’re going to talk about animal communication, specifically the waggle dance of honeybees. When a forager bee finds a good food source, it returns to the hive and performs a series of movements to tell other bees where the food is. The dance consists of a figure-eight pattern, with a straight run in the middle. The angle of the straight run relative to vertical indicates the direction of the food relative to the sun. For example, if the bee runs straight up, the food is directly toward the sun. If it runs at a 45-degree angle to the right, the food is 45 degrees to the right of the sun. The duration of the waggle run, or the number of waggles, indicates the distance. Longer runs signal food that is farther away. Interestingly, bees can adjust their dance based on changes in the sun’s position, showing a remarkable ability to integrate time and spatial information. This discovery, first made by Karl von Frisch, won him the Nobel Prize in 1973. Now, what is the primary purpose of the waggle dance?