Evolutionary Stable Strategies
According to the linked Nature article, interactions between different animals and organisms have costs that can be both beneficial and harmful. For example, when two animals engage in a fight, they both lose resources. On the flip side, when two animals engage in some mutually beneficial behavior such as symbiosis, they both receive a reward. Interactions for which there is one best strategy time and time again, is called an Evolutionary Stable Strategy(ESS). This nature article gives the classic example of the hawk and dove game: When a hawk interacts with a hawk, and a dove interacts with a dove, both pairs have the same outcome. However, the hawks have a lesser outcome than the doves because they are more aggressive and encounter more damage. When a hawk and a dove interact, the hawk ends with a greater outcome than the dove because it is aggressive while the dove is passive. Further, to be an ESS, the total outcome for being a hawk (situations: hawk on hawk and hawk on dove) must be greater than the total payoff for being a dove (situations: dove on dove, dove on hawk). In other words, when there is a dominant strategy: you will receive a higher outcome by being a hawk.
This natural occurrence not only occurs in fights between animals, but also in other interactions. One can generalize the hawk-dove game to other interactions between animals, like when animals are territorial: larger animals are generally more aggressive than smaller animals, because the “likelihood of the larger individual being hurt or killed by the smaller individual is minimal, so the risk of the aggressive behavior is minimal”. Additionally, by being aggressive, they receive the rewards of a larger territory.
Of course, in the real world, it is extremely unlikely that two individuals would receive the same exact payoff as in the hawk-dove game; nevertheless, ESS arises when there is a long term higher reward for choosing one of the options.