Rantsiou, E. | bioRxiv Science

bioRxiv2024

Elephant rumble vocalizations: spectral substructures and superstructures

Elephant communication, particularly through infrasound rumbles, plays a pivotal role in their social interactions, yet the complexity and functional significance of these vocalizations remain only partially understood. This study explores the spectral characteristics of male African Savannah elephant rumbles, revealing a rich substructure within what has traditionally been viewed as homogeneous low-frequency calls. Our formant frequency analysis of wild male elephant rumble vocalizations demonstrates that rumbles exhibit significant within-call spectral variation, challenging the notion of rumbles as uniform acoustic units. Our findings further reveal that elephant rumbles contain complex patterns of frequency modulation, including distinct vowel-like elements, suggestive of sophisticated vocal tract manipulation. We also document the presence of collectively oscillatory behavior in the formant frequencies of elephant rumbles during group vocalization events. This superstructure emerges clearly when silent intervals between rumbles are removed, revealing an oscillatory trend in the chronological sequence of vocalizations. The discovery of intricate spectral substructures and superstructures within elephant rumbles and rumble exchanges respectively, highlights the sophistication of elephant communication systems. This study underlines the elephants ability to engage in complex vocal modulation and may have implications for the understanding of their social organization and cognition. Furthermore, unraveling the complexity of elephant vocalizations can enhance our ability to monitor and conserve these majestic creatures, offering new perspectives for studying their social interactions and behaviors in the wild.

animal behavior and cognition↗

bioRxiv2024

Rules of departure: Antiphony and personalized vocal spaces in wild male elephant group coordination

In the intricate realm of animal communication, vocal signals play a vital role in maintaining bonds and coordinating group activities. Through detailed analysis of low-frequency rumble vocalizations of wild male African Savannah elephants, we demonstrate how these calls are employed in a coordinated manner. Our findings reveal a distinct pattern of call-and-response, usually initiated by a dominant male, with subsequent turn-taking responses from other group members. This antiphonal calling is instrumental in facilitating collective decision-making and group departures, highlighting a sophisticated level of communication previously unrecognized in male elephant groups. Furthermore, the study delves into the frequency content of these rumbles, finding significant individual variations in vocal characteristics. Analysis of the first two formant frequencies of these calls uncovers a distinct vocal space for each elephant, variable over time and across different social contexts. These individualized vocal spaces suggest a mechanism for personal identification within and across elephant groups, and may also relate to the information content of their vocal exchanges. The vocal spaces and structured antiphony presented in this study underline the complexity of elephant vocal communication and invite further targeted research into the vocal communication system of elephants, as well as inquiry into the cognitive and social aspects of wildlife communication in general.

animal behavior and cognition↗