The Significance of Interspecific Social Dominance in Iguanid Lizards

The authors studied an assemblage of large iguanid lizards in an outdoor enclosure at the San Diego (California) Zoo. In this enclosure, an interspecific social dominance pattern was observed. Aggression between lizards of different species resulted in death in the aggressive situations that arose from invasion of territories of the resident animals. The authors suggest that aggression serves as a basic part of territoriality and social hierarchy, and that a continuum exists in social behavior and as space becomes limited, animals will shift from a terri- torial behavior to a social hierarchy that may include members of other species as well as their own.