Meeting Abstract

P1.162  Tuesday, Jan. 4  The dynamic of interspecies aggression: A methodological approach to the study of underwater aggressive behavior CUSICK, J/A*; HERZING, D/L; Florida Atlantic University; Wild Dolphin Project jcusick1@fau.edu

In the Bahamas, two sympatric species of dolphins, Atlantic spotted (Stenella frontalis) and bottlenose (Tursiops truncatus), spend 15% of their time in mixed-species groups. Aggressive behaviors observed in this population are comparable to others documented around the world. For this population, an underwater ethogram was developed that analyzes the dynamic of interspecies aggression. The dynamic of an aggressive encounter is described in terms of the a) individuals involved, b) the direction of the aggression, and c) the behaviors. Aggressive behaviors were broken down into six categories 1) contact, 2) visual, 3) pursuit, 4) sexual displays, 5) group changes, and 6) dynamic shifts. These behaviors are scored in the context of a) experience level of the dolphin (adults versus juveniles), b) male-male associations (adult male spotted dolphin coalitions) versus weak associations between bottlenose dolphins and juvenile male spotted dolphins, c) species dimorphism (bottlenose are larger and more dominant in encounters), and d) the direction of the behavior. This approach presented unique challenges because a dynamic-based ethogram focuses not on the mechanisms of behavior, but on the sequence of behaviors, the relationships between the individuals involved, and the overall outcome of the encounter. A dynamic-based approach will quantify aggressive encounters in terms of a) individuals involved as victim and aggressor and b) shifts in the direction of aggression. This type of analysis could not be accomplished with a mechanism-based ethogram and provides a quantitative analysis of aggression as a whole. It is hypothesized that adult male spotted associations and the bottlenose’s physical dominance will influence the dynamic of the aggressive encounters.