Citation: Communication and Behavior in the Atlantic Spotted Dolphins (Stenella frontalis): Relationships Between Vocal and Behavioral Activities. (August 1996)
Kathleen Maria Dudzinski, B.S., The University of Connecticut Chair of Advisory Committee: Dr. Bernd W
This work presents a description of behaviors and vocalizations of freeranging Atlantic spotted dolphins (Stenella frontalis) in Bahamian waters.The objective is to elucidate mechanisms of intraspecific communication in these dolphins by interpretation of associations between vocal structures, social context, and observed behaviors. The ultimate goal is to evaluate communication and behavior of spotted dolphins in order to eventually understand how an aquatic mammal's sensory abilities permit it to adapt to an environment foreign to terrestrial mammals. While this work does not yield the Rosetta stone to dolphin communication, it does provide a beginning description of associations among their intraspecific interactions, behaviors,and vocalizations. To facilitate this work, I developed a system that allowed concurrent recording of underwater vocal activity and behavior among dolphins. With this system, the vocalizing dolphin could be identified for approximately 38% of all recorded vocalizations, thereby facilitating examination of relationships between an individual's vocalizations, behaviors, age, and gender. Behavior units varied with behavioral activity, group type, and age, but not gender. Some behaviors and vocalizations were produced only by particular ages. For example, melon-to-genital contact was observed between mother/calf dyads, while screams were recorded only from calves and juveniles. Vocal type varied significantly with behavioral activity, group type, and spot class: whistles and chirps were observed mostly during social and play activity, and click trains more during inquisitive and forage modes. No evidence for signature whistles was indicated from the data, although their presence and potential use as contact calls is suggested from anecdotal observations. Spotted dolphins use vocal, visual, and tactile pathways for signal exhange. Behaviors and vocal signals were used concurrently, apparently to maximize or enhance a message. Behaviors and vocalizations were also used separately, but with similar functions. For example, a click train with a chirp produced while one individual approached another appeared to indicate the same message as a pectoral fin to pectoral fin rub between individuals that joined after a separation.