Some of the male lizards (call their type “rock”) use force, invading the territory of fellow males to mate with females. Others (“paper”) favor deception, waiting until females are unguarded and sneaking in. Still others (“scissors”) work by cooperation, joining together to protect one another’s females.The three types of lizard, which the scientists monitored over several years in the French Pyrenees, are locked in a cyclical sort of standoff. For a time, the deceivers flourish at the expense of the intruders, who are too busy marauding to pay attention. Then the cooperators win out over the deceivers, who can’t slink past the guards. And then the intruders vanquish the cooperators, whose openness exposes them to aggression. Then the cycle repeats. It takes about four years.
in 1982, the evolutionary game-theorist John Maynard Smith predicted, using mathematical models of conflict, that such arrangements would be found in nature.