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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 look at how some animals use chemical signals, specifically pheromones. Many people think of pheromones only in the context of mating, but they serve a variety of purposes. For example, ants release alarm pheromones when they detect a threat, which quickly alerts the entire colony to danger. In bees, pheromones help maintain social cohesion, such as the queen’s pheromone that suppresses the development of new queens in the hive. Now, one interesting case is the role of pheromones in kin recognition. Some rodents, like mice, use pheromones to distinguish between relatives and non-relatives, which can influence their social behavior and even mating choices to avoid inbreeding. However, pheromones are not just limited to insects and rodents; they are also found in fish, such as salmon, which use chemical cues to find their way back to their natal streams to spawn. So, as you can see, chemical communication is quite diverse and essential in many animal species.