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Listen to part of a lecture in a biology class. The professor is discussing animal communication. Professor: So, we've talked about visual and auditory signals in animals. But today, I want to focus on a less obvious form: chemical communication, specifically pheromones. Now, pheromones are chemicals released by an animal that affect the behavior or physiology of others of the same species. For example, ants use trail pheromones to mark paths to food sources. But it's not just insects. Many mammals, including dogs, rely heavily on pheromones for social bonding and mating. Interestingly, pheromones can also serve as alarm signals. When a minnow is injured, it releases a chemical that causes nearby minnows to exhibit a fright response, like darting away or freezing. This is an adaptive advantage because it warns others of danger without direct contact. However, detecting pheromones is not always conscious. In some species, the vomeronasal organ, a specialized sense organ, picks up these signals and sends them to the brain, often triggering instinctive reactions. So, unlike visual cues, pheromones can work in darkness and over long distances, making them crucial for survival in certain environments.