Heaviside's dolphins ( Cephalorhynchus heavisidii) relax acoustic crypsis to increase communication range
The costs of predation may exert significant pressure on the mode of communication used by an animal, and many species balance the benefits of communication (e.g. mate attraction) against the potential risk of predation. Four groups of toothed whales have independently evolved narrowband high-freque...
Published in: | Proceedings of the Royal Society B: Biological Sciences |
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Online Access: | http://dx.doi.org/10.1098/rspb.2018.1178 https://royalsocietypublishing.org/doi/pdf/10.1098/rspb.2018.1178 https://royalsocietypublishing.org/doi/full-xml/10.1098/rspb.2018.1178 |
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crroyalsociety:10.1098/rspb.2018.1178 2024-09-15T18:39:13+00:00 Heaviside's dolphins ( Cephalorhynchus heavisidii) relax acoustic crypsis to increase communication range Martin, Morgan J. Gridley, Tess Elwen, Simon H. Jensen, Frants H. Fulbright Association National Geographic Society/Waitt Foundation Emerging Explorers Grant Aarhus Institute of Advanced Studies University of Pretoria Office of Naval Research 2018 http://dx.doi.org/10.1098/rspb.2018.1178 https://royalsocietypublishing.org/doi/pdf/10.1098/rspb.2018.1178 https://royalsocietypublishing.org/doi/full-xml/10.1098/rspb.2018.1178 en eng The Royal Society https://royalsociety.org/journals/ethics-policies/data-sharing-mining/ Proceedings of the Royal Society B: Biological Sciences volume 285, issue 1883, page 20181178 ISSN 0962-8452 1471-2954 journal-article 2018 crroyalsociety https://doi.org/10.1098/rspb.2018.1178 2024-08-12T04:27:43Z The costs of predation may exert significant pressure on the mode of communication used by an animal, and many species balance the benefits of communication (e.g. mate attraction) against the potential risk of predation. Four groups of toothed whales have independently evolved narrowband high-frequency (NBHF) echolocation signals. These signals help NBHF species avoid predation through acoustic crypsis by echolocating and communicating at frequencies inaudible to predators such as mammal-eating killer whales. Heaviside's dolphins ( Cephalorhynchus heavisidii ) are thought to exclusively produce NBHF echolocation clicks with a centroid frequency around 125 kHz and little to no energy below 100 kHz. To test this, we recorded wild Heaviside's dolphins in a sheltered bay in Namibia. We demonstrate that Heaviside's dolphins produce a second type of click with lower frequency and broader bandwidth in a frequency range that is audible to killer whales. These clicks are used in burst-pulses and occasional click series but not foraging buzzes. We evaluate three different hypotheses and conclude that the most likely benefit of these clicks is to decrease transmission directivity and increase conspecific communication range. The expected increase in active space depends on background noise but ranges from 2.5 (Wenz Sea State 6) to 5 times (Wenz Sea State 1) the active space of NBHF signals. This dual click strategy therefore allows these social dolphins to maintain acoustic crypsis during navigation and foraging, and to selectively relax their crypsis to facilitate communication with conspecifics. Article in Journal/Newspaper toothed whales The Royal Society Proceedings of the Royal Society B: Biological Sciences 285 1883 20181178 |
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crroyalsociety |
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English |
description |
The costs of predation may exert significant pressure on the mode of communication used by an animal, and many species balance the benefits of communication (e.g. mate attraction) against the potential risk of predation. Four groups of toothed whales have independently evolved narrowband high-frequency (NBHF) echolocation signals. These signals help NBHF species avoid predation through acoustic crypsis by echolocating and communicating at frequencies inaudible to predators such as mammal-eating killer whales. Heaviside's dolphins ( Cephalorhynchus heavisidii ) are thought to exclusively produce NBHF echolocation clicks with a centroid frequency around 125 kHz and little to no energy below 100 kHz. To test this, we recorded wild Heaviside's dolphins in a sheltered bay in Namibia. We demonstrate that Heaviside's dolphins produce a second type of click with lower frequency and broader bandwidth in a frequency range that is audible to killer whales. These clicks are used in burst-pulses and occasional click series but not foraging buzzes. We evaluate three different hypotheses and conclude that the most likely benefit of these clicks is to decrease transmission directivity and increase conspecific communication range. The expected increase in active space depends on background noise but ranges from 2.5 (Wenz Sea State 6) to 5 times (Wenz Sea State 1) the active space of NBHF signals. This dual click strategy therefore allows these social dolphins to maintain acoustic crypsis during navigation and foraging, and to selectively relax their crypsis to facilitate communication with conspecifics. |
author2 |
Fulbright Association National Geographic Society/Waitt Foundation Emerging Explorers Grant Aarhus Institute of Advanced Studies University of Pretoria Office of Naval Research |
format |
Article in Journal/Newspaper |
author |
Martin, Morgan J. Gridley, Tess Elwen, Simon H. Jensen, Frants H. |
spellingShingle |
Martin, Morgan J. Gridley, Tess Elwen, Simon H. Jensen, Frants H. Heaviside's dolphins ( Cephalorhynchus heavisidii) relax acoustic crypsis to increase communication range |
author_facet |
Martin, Morgan J. Gridley, Tess Elwen, Simon H. Jensen, Frants H. |
author_sort |
Martin, Morgan J. |
title |
Heaviside's dolphins ( Cephalorhynchus heavisidii) relax acoustic crypsis to increase communication range |
title_short |
Heaviside's dolphins ( Cephalorhynchus heavisidii) relax acoustic crypsis to increase communication range |
title_full |
Heaviside's dolphins ( Cephalorhynchus heavisidii) relax acoustic crypsis to increase communication range |
title_fullStr |
Heaviside's dolphins ( Cephalorhynchus heavisidii) relax acoustic crypsis to increase communication range |
title_full_unstemmed |
Heaviside's dolphins ( Cephalorhynchus heavisidii) relax acoustic crypsis to increase communication range |
title_sort |
heaviside's dolphins ( cephalorhynchus heavisidii) relax acoustic crypsis to increase communication range |
publisher |
The Royal Society |
publishDate |
2018 |
url |
http://dx.doi.org/10.1098/rspb.2018.1178 https://royalsocietypublishing.org/doi/pdf/10.1098/rspb.2018.1178 https://royalsocietypublishing.org/doi/full-xml/10.1098/rspb.2018.1178 |
genre |
toothed whales |
genre_facet |
toothed whales |
op_source |
Proceedings of the Royal Society B: Biological Sciences volume 285, issue 1883, page 20181178 ISSN 0962-8452 1471-2954 |
op_rights |
https://royalsociety.org/journals/ethics-policies/data-sharing-mining/ |
op_doi |
https://doi.org/10.1098/rspb.2018.1178 |
container_title |
Proceedings of the Royal Society B: Biological Sciences |
container_volume |
285 |
container_issue |
1883 |
container_start_page |
20181178 |
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1810483611805155328 |