Male associations are a typical component of elephant society, allowing bulls to practice appropriate social behavior. To improve zoo elephant welfare, it is important to provide bulls with social opportunities. In fall 2018, Denver Zoo added two bull Asian elephants to its existing all-male group of three bulls, offering the opportunity to conduct a systematic behavioral study of the integration of the new bulls into the resident group. We recorded aggressive and affiliative behaviors before, during, and after the introduction of the new males. The proportion of aggressive behavior was significantly higher during the five-month introduction period compared to before their introduction. By the end of the study period, the elephants engaged in significantly more affiliative behavior and less aggressive behavior than during the introduction period, suggesting they had formed a new stable social dynamic. These results suggest group compatibility and positive elephant welfare resulting from housing male elephants together and can be used to inform management plans for bull elephants that prioritize their welfare.
Keywords: Bull elephant welfare; group compatibility; group integration; social behavior.