Anti Gravity: The Lizard Kings; June 1996; Scientific American Magazine; by Mirsky; 1 Page(s)

About halfway between Fresno and San Jose, in California¿s Merced County, a tiny creature is stuck in an endless cycle, in which winning guarantees imminent defeat, and losing only foreshadows a brighter future. The creature is the side-blotched lizard, Uta stansburiana, for which evolution has designed a unique chore: three distinct male types are caught in a living version of the rock-paperscissors game. In a recent issue of Nature, Barry Sinervo and Curtis M. Lively of Indiana University describe this first example of a species in which the population frequency of males is determined by a cycle involving three different forms of male.

In the rock-paper-scissors game, paper always covers rock, scissors always cut paper, and rock always breaks scissors, only to be covered by paper again, and so on. In the lizard version, mating is the objective: orange- throated males beat out bluethroats, blue-throats overpower yellow- striped throats and yellow-striped throats checkmate orange-throats. These relations have generated a sixyear cycle in which the three distinct morphs take turns being predominant.