Social behavior and pheromonal communication in reptiles

The role of pheromones in orchestrating social behaviors in reptiles is reviewed. Although all reptile orders are examined, the vast majority of the literature has dealt only with squamates, primarily snakes and lizards. The literature is surprisingly large, but most studies have explored relatively few behaviors. The evolution of chemical signaling in reptiles is discussed along with behaviors governed by pheromones including conspecific trailing, male-male agonistic interactions, sex recognition and sex pheromones, and reptilian predator recognition. Nonreptilian prey recognition by chemical cues was not reviewed. The recent literature has focused on two model systems where extensive chemical ecology studies have been conducted: the reproductive ecology of garter snakes and the behavioral ecology of Iberian lacertid lizards. In these two systems, enough is known about the chemical constituents that mediate behaviors to explore the evolution of chemical signaling mechanisms that affect life history patterns. In addition, these models illuminate natural and sexual selection processes which have lead to complex chemical signals whose different components and concentrations provide essential information about individuals to conspecifics. Reptiles provide excellent candidates for further studies in this regard not only in squamates, but also in the orders where little experimental work has been conducted to date.