The Evolution of Reptilian Social Behavior

Abstract

Reptiles display a diversity of behavior that is reflective of their evolutionary heritage from fish and amphibians and their ancestral contribution to the diversity found in birds and mammals. Much of the behavior observed in reptiles seems specific to the ecological setting within which they live. As a result, a diversity of behavior is found in each of the groups of modern reptiles. Recent studies on the social behavior of lizards have proved them capable of a variety of behavioral postures, sequences, and sociality that exceeds that found in some mammals and birds. While many species of lizards are territorial, others are hierarchial and some have harems. For all those territorial species studied, crowding results in increased social interaction, increased aggression, and a switch to hierarchial behavior. While smell and sound may be important stimuli for social behavior in some reptiles, posture, actions, and especially color appear to be most important in diurnal lizards. Temperature and energy studies suggest that the large extinct dinosaurs probably fought considerably less than commonly portrayed in movies and stories, but were also probably much more brightly colored than commonly shown in reconstructions.