Antiphonal exchanges in female African elephants

Abstract

Female African elephants (Loxodonta africana) engage in antiphonal exchanges of rumble vocalizations. In this study, female African elephants (N=7) housed at Disney’s Animal Kingdom were outfitted with audio-recording collars and videotaped during 50 1-hour observation sessions (conducted in 2002). We found that production of the antiphonal response rumble reflected changes in herd affiliation that had taken place since our previous study (2000). Second, we examined response latency and found that females responded more quickly to the rumbles of affiliated partners than to those of a nonaffiliated female. Since affiliated partners spend more time in close proximity by definition, they may engage in higher rates of temporally associated calling simply because nearby stimuli impact them simultaneously or due to a social facilitation effect, not because they are true vocal exchanges. Therefore, we examined antiphonal rumble responses when female pairs were more than 25 m apart. We found that at these distances, affiliated females still exchanged rumbles more frequently, and responded at a decreased latency, than nonaffiliated pairs. Our results provide support for functional hypotheses of African elephant rumble vocalizations that require instances of temporally associated calling in order to be true communicative events. [Work supported by Grant No. NSF-IIS-0326395.]