Male lizard cooperation adds new wrinkle to evolutionary theory

Blue-throated lizards that help each other achieve reproductive success are also helping scientists understand how social cooperation evolved. Most examples of cooperative behavior in animals involve cooperation between genetically related individuals, which is explained by the theory of “kin selection.” Now, researchers have described an example of cooperation between genetically similar but unrelated members of a lizard species common in the western United States. Their findings, published in the June 20 issue of the journal Science, shed new light on the evolution of cooperation and social behavior.