A QUANTITATIVE ASSESSMENT OF DOMINANCE RELATIONS AMONG BOTTLE-NOSED DOLPHINS

Agonistic behavior of bottlenose dolphins was studied at Brookfield Zo o for nearly 4.5 yr, and dominance relationships were determined using a quantitative technique adapted from primate behavioral research. Do minance relations among dolphins were influenced by the gender of part icipants. Male dolphins were clearly and consistently dominant: to fem ales, and intersexual agonism occurred at moderate races with seasonal peaks in spring and fall. Dominance relationships among female dolphi ns were age-ordered and stable, even though agonism among females did occur at uniformly low rates. In contrast, the two males had a changea ble dominance relationship in which periods of stability and low-level agonism were interspersed with episodes of intense competition. Zoo-b ased research revealed patterns of behavior that conformed to current knowledge about bottlenose dolphin social structure. Moreover, researc h in a zoo setting facilitated development of a quantitative technique that can be used to assess cetacean dominance relationships in field research.