What is ritualization in the evolution of animal signals?

In the study of animal behaviour, ritualization is the evolutionary process by which ordinary behaviours, physiological processes, or body structures are transformed into specialized signals.12

New signals do not emerge from scratch; instead, they evolve from existing "protosignals"—actions like preening, feeding, or intention movements (such as baring teeth before an attack) that originally served non-signaling functions. Through ritualization, these precursors undergo a distinct evolutionary trajectory characterized by two primary changes:1

• Reduction: The number of components in the original behaviour is often decreased.1
• Exaggeration: Remaining components are amplified or stylized to become more conspicuous.1

For example, visual signals may be enhanced through the addition of colour or the elongation of body structures like fins and feathers, while auditory signals may be modulated or repeated to stand out against environmental noise. This process ensures that the signal is distinct and effectively communicates information—such as aggressive intent, submissiveness, or reproductive state—between the sender and receiver. Over time, the receiver's sensory organs may also become fine-tuned to better detect these emphasized signal components, facilitating the coevolution of both signaling and receiving mechanisms.12