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The Role of Asymmetry of the Left and Right External Ear of Bottlenose Dolphin (Tursiops truncatus) in the Spatial Localization of Sound

  • ACOUSTICS OF LIVING SYSTEMS. BIOMEDICAL ACOUSTICS
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Abstract

It is generally accepted that Odontoceti lost their external ears (pinnae) in the process of adapting to aquatic habitats. However, their hearing localizes sound with an accuracy of 1° in the frontal and median planes and is directional. These facts indicate the presence of morphological structures functionally performing the role of evolutionarily new external ears adapted to the aquatic environment. The data available to date suggest that this role is played by the left and right row of mental foramens (MFs) and the morphological structures of the rostrum and skull of the dolphin. In this study, for the first time for Odontoceti, the paths of sound travel along MFs and mandibular canals of the lower jaw of bottlenose dolphin (Tursiops truncatus) are measured, and the relative time delays of sound between the MF and the degree of their acoustic shielding by the rostrum and skull depending on the localization of sound in space are calculated. It was established that the left and right outer ear form unique temporal and spectral signs of the spatial localization of sound with a maximal accuracy realized rostrally. Localization mechanisms are based on asymmetry, including rostral–caudal and left–right mutually complementary asymmetry of MF architecture, dorsal–ventral asymmetry in the size of the rostrum, as well as rostral–ventral asymmetry in the position of the left and right row of MFs on the rostrum and rostral–caudal asymmetry in the sizes of the rostrum and skull. Thus, unlike the outer ears of terrestrial animals and human beings limited by the auricles, the outer ears of the dolphin are integrated into the streamlined shape of the rostrum and head of the dolphin, which reduces the resistance to its movement from the water side and, most importantly, does not worsen the signal-to-noise ratio of the flow around it in its hearing with increasing speed. Based on the morphology similarity of Odontoceti, it is natural to assume that their MFs and the morphological structures of the rostrum and skull play the role of external ears and form signs of spatial localization of sounds.

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REFERENCES

  1. D. L. Renaud and A. N. Popper, J. Exp. Biol. 63, 569 (1975).

    Article  Google Scholar 

  2. L. D. Korolev, N. V. Lipatov, R. N. Rezvov, M. A. Savel’ev, and A. B. Flenov, in Proc. 8th All-Union Acoustical Conf. (Moscow, 1973), Vol. 1, p. 125.

  3. B. K. Branstetter, S. J. Mevissen, L. M. Herman, et al., Bioacoustics, No. 14, 15 (2003).

    Article  Google Scholar 

  4. J. A. Simmons, S. A. Kick, B. D. Lawrence, C. Hale, C. Bard, and B. Escudie, J. Comp. Physiol. 153, 321 (1983).

    Article  Google Scholar 

  5. J. Blauert, Spatial Hearing: the Psychophysics of Human Sound Localization (MIT Press, Cambridge, MA, 1997).

    Google Scholar 

  6. R. M. Warren, Auditory Perception: a New Analysis and Synthesis (Cambridge Univ. Press, Cambridge, 1999).

    Google Scholar 

  7. R. A. Butler, R. A. Humanski, and A. D. Musicant, Perception 19, 241 (1990).

    Article  Google Scholar 

  8. M. B. Gardner, J. Acoust. Soc. Am. 54 (6), 1489 (1973).

    Article  ADS  Google Scholar 

  9. R. A. Butler, in Handbook of Sensory Physiology (Springer-Verlag, Berlin, 1975), Vol. 5(2), p. 247.

  10. I. A. Gorlinsky and A. I. Konstantinov, in Proc. 4th Int. Bat Research Conf. (Nairobi, 1978), p. 145.

  11. R. A. Norberg, Phil. Trans. R. Soc. London Ser. B 280, 375 (1977).

    Article  ADS  Google Scholar 

  12. E. I. Knudsen and M. Konishi, J. Comp. Physiol. A 133, 13 (1979).

    Article  Google Scholar 

  13. D. R. Ketten, IEEE. Proc. Underwater Acoust. 1, 264 (1994).

    Google Scholar 

  14. W. W. L. Au and P. W. B. Moore, J. Acoust. Soc. Am. 75 (1), 255 (1984).

    Article  ADS  Google Scholar 

  15. E. V. Romanenko, Acoust. Phys. 65 (1), 103 (2019).

    Article  ADS  Google Scholar 

  16. F. C. Fraser and P. E. Purves, Bull. Brit. Mus. Nat. Hist., Zool. 7 (1), 1 (1960).

    Google Scholar 

  17. K. S. Norris, in Evolution and Environment, Ed. by E. Drake (Yale Univ. Press, New Heaven, 1968), p. 297.

  18. V. V. Popov, A. Ya. Supin, V. O. Klishin, et al., J. Acoust. Soc. Am. 123 (1), 552 (2008).

    Article  ADS  Google Scholar 

  19. T. W. Cranford, P. Krysl, and J. A. Hildebrand, Bioinspir. Biomimet. 3, 1 (2008).

    Article  Google Scholar 

  20. V. A. Ryabov, J. Acoust. Soc. Am. 1144, 2414 (2003).

    Article  ADS  Google Scholar 

  21. V. A. Ryabov, in Proc. 3rd Int. Conf. Marine Mammals of the Holarctic, Koktebel, Crimea, Oct. 11–17, 2004 (Moscow, 2004), p. 483.

  22. V. A. Ryabov, Nat. Sci. 2 (6), 646 (2010). https://doi.org/10.4236/ns.2010.26081

    Article  Google Scholar 

  23. V. A. Ryabov, Biophysics 59 (3), 475 (2014).

    Article  Google Scholar 

  24. V. A. Ryabov, St. Petersburg Polytech. Univ. J.: Phys. Math. 2, 240 (2016). https://doi.org/10.1016/j.spjpm.2016.08.003

    Article  Google Scholar 

  25. G. B. Agarkov, B. G. Khomenko, and V. G. Khadzhinskii, Dolphins Morphology (Naukova dumka, Kiev, 1974) [in Russian].

    Google Scholar 

  26. C. Barroso, T. W. Cranford, and A. Berta, J. Morphol. 273 (9), 1021 (2012). https://doi.org/10.1002/jmor.20040

    Article  Google Scholar 

  27. U. Varanasi and D. C. Malins, Biochim. Biophys. Acta 231, 415 (1971).

    Article  Google Scholar 

  28. D. R. Ketten, The Biology of Hearing, Ed. by D. Webster, R. Fay, and A. Popper (Springer-Verlag, New York, 1992), Vol. 13, No. 2, p. 43.

  29. S. H. Ridgway and W. W. L. Au, Encyclopedia of Neuroscience (Elsevier, Madrid, 2009), Vol. 4, p. 1031. https://doi.org/10.1016/B978-008045046-9.00263-1

    Book  Google Scholar 

  30. W. W. L. Au, The Sonar of Dolphins (Springer-Verlag, New York, 1993).

    Book  Google Scholar 

  31. P. W. B. Moore, D. A. Pawloski, and L. A. Dankiewicz, in Sensory Systems of Aquatic Mammals, Ed. by R. A. Kastelein, J. A. Thomas, and P. E. Nachtigall (De Spil, Woerden, 1995), p. 11.

  32. M. P. Ivanov, S. N. Butov, L. E. Leonova, E. V. Romanovskaya, and V. E. Stefanov, Acoust. Phys. 65 (5), 603 (2019).

    Article  ADS  Google Scholar 

  33. K. A. Rossbach and D. L. Herzing, Mar. Mammal Sci. 13, 498 (1997).

    Article  Google Scholar 

  34. V. E. Pyatetskii and V. M. Shakalo, Bionika 9, 46 (1975).

    Google Scholar 

  35. E. V. Romanenko and E. G. Yanov, in Marine Mammals. Research Results (Nauka, Moscow, 1978), p. 241 [in Russian].

    Google Scholar 

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ACKNOWLEDGMENTS

The author expresses his gratitude to the staff of the Laboratory of Marine Mammals at the Vyazemsky Karadag scientific station of the Russian Academy of Sciences, a branch of the Federal State Budgetary Institution of the Federal Research Center “Kovalevsky Institute of Biology of the Southern Seas, Russian Academy of Sciences” and, especially, to the trainers S. Yakhno and N. Zhukova for their invaluable help in carrying out the study.

Funding

This work was supported by a state order, no. 121032300019-0.

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Authors and Affiliations

  1. Vyazemsky Karadag Scientific Station—Natural Reserve of Russian Academy of Sciences, Branch of Federal Research Center “Kovalevsky Institute of Biology of the Southern Seas, Russian Academy of Sciences”, 298188, Feodosiya, Russia

    V. A. Ryabov

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Correspondence to V. A. Ryabov.

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Translated by A. Ivanov

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Ryabov, V.A. The Role of Asymmetry of the Left and Right External Ear of Bottlenose Dolphin (Tursiops truncatus) in the Spatial Localization of Sound. Acoust. Phys. 69, 119–131 (2023). https://doi.org/10.1134/S1063771022060112

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