Heaviside's dolphins (Cephalorhynchus heavisidii) relax acoustic crypsis to increase communication range
| Autor: | Morgan Jennifer Martin, Frants H. Jensen, Simon Harvey Elwen, Tess Gridley |
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| Jazyk: | angličtina |
| Rok vydání: | 2018 |
| Předmět: |
0106 biological sciences
Computer science Acoustics Human echolocation 010603 evolutionary biology 01 natural sciences General Biochemistry Genetics and Molecular Biology symbols.namesake Narrowband high-frequency clicks Statistical analyses 0103 physical sciences Range (statistics) 010301 acoustics General Environmental Science General Immunology and Microbiology biology Heaviside step function Communication General Medicine biology.organism_classification Heaviside's dolphin Active space Cephalorhynchus heavisidii Echolocation Crypsis symbols General Agricultural and Biological Sciences Acoustic crypsis Relevant information |
| Zdroj: | Martin, M J, Gridley, T, Elwen, S H & Jensen, F H 2018, ' Heaviside's dolphins (Cephalorhynchus heavisidii) relax acoustic crypsis to increase communication range ', Proceedings of the Royal Society B: Biological Sciences, vol. 285, no. 1883, 20181178 . https://doi.org/10.1098/rspb.2018.1178 Martin, M J, Gridley, T, Elwen, S H & Jensen, F H 2018, ' Heavisides dolphins (Cephalorhynchus heavisidii) relax acoustic crypsis to increase communication range ' Proceedings of the Royal Society B: Biological Sciences, vol. 285, no. 1883, 20181178 . https://doi.org/10.1098/rspb.2018.1178 |
| DOI: | 10.1098/rspb.2018.1178 |
| Popis: | 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. |
| Databáze: | OpenAIRE |
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