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dc.contributor.authorGötz, Thomas
dc.contributor.authorPacini, Aude F.
dc.contributor.authorNachtigall, Paul
dc.contributor.authorJanik, Vincent M.
dc.identifier.citationGötz , T , Pacini , A F , Nachtigall , P & Janik , V M 2020 , ' The startle reflex in echolocating odontocetes : basic physiology and practical implications ' , Journal of Experimental Biology , vol. 223 , jeb208470 .
dc.identifier.otherPURE: 262037582
dc.identifier.otherPURE UUID: 7b8da864-de5e-4817-9c18-6e4403360e63
dc.identifier.otherORCID: /0000-0001-7894-0121/work/70619130
dc.identifier.otherORCID: /0000-0002-4630-3328/work/71221491
dc.identifier.otherScopus: 85081924852
dc.identifier.otherWOS: 000541826200003
dc.descriptionThis study was funded by Marine Scotland (Scottish Government). Open Access funding provided by The University of St Andrews.en
dc.description.abstractThe acoustic startle reflex is an oligo-synaptic reflex arc elicited by rapid-onset sounds. Odontocetes evolved a range of specific auditory adaptations to aquatic hearing and echolocation, e.g. the ability to downregulate their auditory sensitivity when emitting clicks. However, it remains unclear whether these adaptations also led to changes of the startle reflex. We investigated reactions to startling sounds in two bottlenose dolphins (Tursiops truncatus) and one false killer whale (Pseudorca crassidens). Animals were exposed to 50 ms, 1/3 octave band noise pulses of varying levels at frequencies of 1, 10, 25 and 32 kHz while positioned in a hoop station. Startle responses were quantified by measuring rapid muscle contractions using a three-dimensional accelerometer attached to the dolphin. Startle magnitude increased exponentially with increasing received levels. Startle thresholds were frequency dependent and ranged from 131 dB at 32 kHz to 153 dB at 1 kHz (re. 1 µPa). Startle thresholds only exceeded masked auditory AEP thresholds of the animals by 47 dB but were ∼82 dB above published behavioural audiograms for these species. We also tested the effect of stimulus rise time on startle magnitude using a broadband noise pulse. Startle responses decreased with increasing rise times from 2 to 100 ms. Models suggested that rise times of 141–220 ms were necessary to completely mitigate startle responses. Our data showed that the startle reflex is conserved in odontocetes and follows similar principles as in terrestrial mammals. These principles should be considered when assessing and mitigating the effects of anthropogenic noise on marine mammals.
dc.relation.ispartofJournal of Experimental Biologyen
dc.rightsCopyright © 2020. Published by The Company of Biologists Ltd This is an Open Access article distributed under the terms of the Creative Commons Attribution License (, which permits unrestricted use, distribution and reproduction in any medium provided that the original work is properly attributed.en
dc.subjectAcoustic startle reflexen
dc.subjectHearing thresholdsen
dc.subjectStartle thresholdsen
dc.subjectRise timeen
dc.subjectAnthropogenic noiseen
dc.subjectBottlenose dolphinen
dc.subjectQH301 Biologyen
dc.titleThe startle reflex in echolocating odontocetes : basic physiology and practical implicationsen
dc.typeJournal articleen
dc.description.versionPublisher PDFen
dc.contributor.institutionUniversity of St Andrews.Sea Mammal Research Uniten
dc.contributor.institutionUniversity of St Andrews.Scottish Oceans Instituteen
dc.contributor.institutionUniversity of St Andrews.School of Biologyen
dc.contributor.institutionUniversity of St Andrews.Marine Alliance for Science & Technology Scotlanden
dc.contributor.institutionUniversity of St Andrews.Institute of Behavioural and Neural Sciencesen
dc.contributor.institutionUniversity of St Andrews.Centre for Social Learning & Cognitive Evolutionen
dc.contributor.institutionUniversity of St Andrews.Bioacoustics groupen
dc.description.statusPeer revieweden

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