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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 how animals communicate, and specifically, the role of chemical signals, or pheromones. Now, you might think that chemical communication is slow and less precise than visual or auditory signals. But in many species, it’s actually the most reliable method. For example, ants release pheromones to mark trails to food sources. This chemical trail can persist for hours, guiding other ants even after the original ant has returned to the nest. Another example is in mammals, like dogs, which use urine to signal territory boundaries. These signals can convey information about the animal’s identity, reproductive status, and even health. Interestingly, pheromones are often processed by a specialized organ called the vomeronasal organ, which is separate from the main olfactory system. This organ sends signals directly to the amygdala, a brain region involved in emotion and memory, which may explain why chemical signals can trigger strong, immediate behavioral responses. So, while chemical communication might seem less flashy, it has distinct advantages, especially in dark or dense environments where visual signals are ineffective.