Publication Date:
2022-11-07
Description:
© The Author(s), 2022. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Lehmann, K. D. S., Jensen, F. H., Gersick, A. S., Strandburg-Peshkin, A., & Holekamp, K. E. Long-distance vocalizations of spotted hyenas contain individual, but not group, signatures. Proceedings of the Royal Society B: Biological Sciences, 289(1979), (2022): 20220548, https://doi.org/10.1098/rspb.2022.0548.
Description:
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.
Description:
This work was supported by National Science Foundation grant nos OISE1853934 and IOS1755089, Carlsberg Foundation grant no. CF 15-0915 and Human Frontier Science Program grant no. RGP0051/2019. K.D.S.L. was supported by a Graduate Research Fellowship from NSF. A.S.P. received additional funding from the Gips-Schüle Stiftung, the Max Planck Institute of Animal Behaviour, and the Zukunftskolleg at the University of Konstanz. F.H.J. was funded through an AIAS-COFUND fellowship from Aarhus Institute of Advanced Studies under the FP7-PEOPLE programme of the EU (agreement no. 609033).
Keywords:
Long-distance signals
;
Animal communication
;
Group signatures
;
Individual signatures
Repository Name:
Woods Hole Open Access Server
Type:
Article
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