Animals that are toxic, armed with spines, or are otherwise unpalatable, or disagreeable, to predators often exhibit conspicuous colors or patterns. These superficial characteristics, called aposematic signals, are used to warn potential predators of the animal's physical or chemical defenses. The distinct colorations are highly conspicuous against certain backgrounds. This imposes a cost on the aposematic prey because the predators can more readily spot them. However, the predators will also be quick to learn and remember which prey to avoid because of the distinctiveness of the signals. Of course, if the prey is not sufficiently unpalatable, then the costs are greater than the benefits for the attacked animal.

To evaluate whether the benefits outweigh the costs of any predator/prey strategy, the Evolutionary Stable Strategy (ESS) should be taken into account. The ESS is a strategy that, when common among members of a particular role—such as aposematic...