Nghe TOEFL

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Listen to part of a lecture in a biology class. The professor is discussing animal communication. Professor: Today we're going to talk about the honeybee's waggle dance, a fascinating example of symbolic communication. When a foraging honeybee returns to the hive after finding a rich nectar source, it performs a series of movements on the vertical surface of the honeycomb. This dance, first decoded by Karl von Frisch in the 1940s, conveys two critical pieces of information: the distance and the direction of the food source. The distance is indicated by the duration of the waggle phase—the longer the waggle, the farther the food. Direction is communicated through the angle of the dance relative to the vertical, which corresponds to the angle of the food source relative to the sun. Interestingly, the bee also adjusts its dance based on the quality of the nectar, performing more vigorous dances for higher-quality sources. This abstract encoding of spatial information was once thought to be unique to honeybees, but we now know that some other insects and even certain birds use similar symbolic signals. So, the waggle dance is not just a simple cue; it's a true language.