Skip to content

Research at St Andrews

The startle reflex in echolocating odontocetes: basic physiology and practical implications

Research output: Contribution to journalArticle

DOI

Open Access permissions

Open

Abstract

The 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.
Close

Details

Original languageEnglish
Article numberjeb208470
Number of pages12
JournalJournal of Experimental Biology
Volume223
Early online date12 Mar 2020
DOIs
Publication statusE-pub ahead of print - 12 Mar 2020

    Research areas

  • Acoustic startle reflex, Hearing thresholds, Startle thresholds, Rise time, Anthropogenic noise, Bottlenose dolphin, Tursiops, Pseudorca, Brainstem

Discover related content
Find related publications, people, projects and more using interactive charts.

View graph of relations

Related by author

  1. Effects of impulsive noise on marine mammals: investigating range-dependent risk

    Hastie, G., Merchant, N., Goetz, T., Russell, D. J. F., Thompson, P. & Janik, V. M., Jul 2019, In : Ecological Applications. 29, 5, 10 p., e01906.

    Research output: Contribution to journalArticle

  2. Can fear conditioning repel California sea lions from fishing activities?

    Schakner, Z. A., Götz, T., Janik, V. M. & Blumstein, D. T., Oct 2017, In : Animal Conservation. 20, 5, p. 425-432 8 p.

    Research output: Contribution to journalArticle

  3. The startle reflex in acoustic deterrence: an approach with universal applicability?

    Goetz, T. & Janik, V. M., 20 Jun 2016, In : Animal Conservation. 19, p. 225-226

    Research output: Contribution to journalArticle

  4. Potential uses of anthropogenic noise as a source of information in animal sensory and communication systems

    Stansbury, A., Deecke, V., Gotz, T. & Janik, V. M., 1 Jan 2016, The Effects of Noise on Aquatic Life II. Popper, A. N. & Hawkins, A. (eds.). Springer, p. 1105-1111 (Advances in Experimental Medicine and Biology; vol. 875).

    Research output: Chapter in Book/Report/Conference proceedingConference contribution

Related by journal

  1. Acceleration-triggered animal-borne videos show a dominance of fish in the diet of female northern elephant seals

    Yoshino, K., Takahashi, A., Adachi, T., Costa, D. P., Robinson, P. W., Peterson, S. H., Hückstädt, L. A., Holser, R. R. & Naito, Y., 28 Feb 2020, In : Journal of Experimental Biology. 223, 5, 9 p., jeb212936.

    Research output: Contribution to journalArticle

  2. Dynamic biosonar adjustment strategies in deep-diving Risso's dolphins driven partly by prey evasion

    Jensen, F. H., Keller, O. A., Tyack, P. L. & Visser, F., Feb 2020, In : Journal of Experimental Biology. 223, 9 p., jeb216283.

    Research output: Contribution to journalArticle

  3. Energy compensation and received echo level dynamics in constant-frequency bats during active target approaches

    Stidsholt, L., Müller, R., Beedholm, K., Ma, H., Johnson, M. & Madsen, P. T., 28 Jan 2020, In : Journal of Experimental Biology. 223, 2, 9 p., jeb217109.

    Research output: Contribution to journalArticle

  4. Flash and grab: deep-diving southern elephant seals trigger anti-predator flashes in bioluminescent prey

    Goulet, P., Guinet, C., Campagna, C., Campagna, J., Tyack, P. L. & Johnson, M., 19 May 2020, In : Journal of Experimental Biology. 223, 10, 11 p., jeb.222810.

    Research output: Contribution to journalArticle

ID: 262037582

Top