How do animal signals help receivers decide whether to fight or flee?

In the context of animal communication, signals serve as vital tools that allow individuals to assess their opponents and make informed decisions about whether to engage in a fight or retreat.12

The Role of Assessment

When two animals compete for a nonsharable resource, such as food, a mate, or a territory, they often engage in reciprocal communication to resolve the conflict without resorting to dangerous, escalated fighting. Receivers use these signals to evaluate the relative fighting ability, motivation, and physical condition of their opponent. By integrating this information with their own prior experience and inherited biases, a receiver can determine if the cost of fighting—such as the risk of injury or energy expenditure—outweighs the potential benefit of winning.3415

Signal Mechanisms

• Honest Indicators: Signals often provide reliable information about a sender's strength. For example, low-frequency sounds are often associated with larger body sizes, signaling that an opponent may be too formidable to challenge.16
• Ritualized Displays: Many species use ritualized intention movements, such as posturing or roaring, to communicate status or intent. For instance, red deer stags roar at each other to assess relative stamina; if a challenger cannot match the roar rate of the defender, it may withdraw to avoid injury.467
• Status Badges: In some species, physical traits like plumage patterns serve as "badges of status," allowing individuals to recognize dominant rivals and avoid unnecessary conflicts.45

Ultimately, these signals function as a mechanism to minimize the costs of aggression. When a receiver perceives that it is likely to lose based on the signals provided, it may choose to flee or submit, thereby avoiding the physical harm associated with an escalated encounter.147