Long-distance vocalizations of spotted hyenas contain individual, but not group, signatures

Authors

Kenna D.S. Lehmann, University of Nebraska-LincolnFollow
Frants H. Jensen, Syracuse UniversityFollow
Andrew Gersick, Princeton UniversityFollow
Ariana Strandburg-Peshkin, Universität KonstanzFollow
Kay E. Holekamp, Michigan State UniversityFollow

Date of this Version

7-27-2022

Citation

Lehmann KDS, Jensen FH, Gersick AS, Strandburg-Peshkin A, Holekamp KE. 2022 Long-distance vocalizations of spotted hyenas contain individual, but not group, signatures. Proc. R. Soc. B 289: 20220548. https://doi.org/10.1098/rspb.2022.0548

Comments

© 2022 The Authors. Published by the Royal Society under the terms of the Creative Commons Attribution License

Electronic supplementary material is attached below and is also available online at https://doi.org/10.6084/m9.figshare. c.6080858

Abstract

In animal societies, identity signals are common, mediate interactions within groups, and allow individuals to discriminate group-mates from out-group competitors. However, individual recognition becomes increasingly challenging as group size increases and as signals must be transmitted over greater distances. Group vocal signatures may evolve when successful in-group/out-group distinctions are at the crux of fitness-relevant decisions, but group signatures alone are insufficient when differentiated within-group relationships are important for decision-making. Spotted hyenas are social carnivores that live in stable clans of less than 125 individuals composed of multiple unrelated matrilines. Clan members cooperate to defend resources and communal territories from neighbouring clans and other mega carnivores; this collective defence is mediated by long-range (up to 5 km range) recruitment vocalizations, called whoops. Here, we use machine learning to determine that spotted hyena whoops contain individual but not group signatures, and that fundamental frequency features which propagate well are critical for individual discrimination. For effective clan-level cooperation, hyenas face the cognitive challenge of remembering and recognizing individual voices at long range. We show that serial redundancy in whoop bouts increases individual classification accuracy and thus extended call bouts used by hyenas probably evolved to overcome the challenges of communicating individual identity at long distance.