A Discussion on the 'Ear' Under Water || Some Aspects of Mammalian Hearing under Water

Embed Size (px)

Text of A Discussion on the 'Ear' Under Water || Some Aspects of Mammalian Hearing under Water

  • Some Aspects of Mammalian Hearing under WaterAuthor(s): F. W. Reysenbach De HaanSource: Proceedings of the Royal Society of London. Series B, Biological Sciences, Vol. 152, No.946, A Discussion on the 'Ear' Under Water (Apr. 26, 1960), pp. 54-62Published by: The Royal SocietyStable URL: http://www.jstor.org/stable/75363 .Accessed: 07/05/2014 14:52

    Your use of the JSTOR archive indicates your acceptance of the Terms & Conditions of Use, available at .http://www.jstor.org/page/info/about/policies/terms.jsp

    .JSTOR is a not-for-profit service that helps scholars, researchers, and students discover, use, and build upon a wide range ofcontent in a trusted digital archive. We use information technology and tools to increase productivity and facilitate new formsof scholarship. For more information about JSTOR, please contact support@jstor.org.

    .

    The Royal Society is collaborating with JSTOR to digitize, preserve and extend access to Proceedings of theRoyal Society of London. Series B, Biological Sciences.

    http://www.jstor.org

    This content downloaded from 169.229.32.136 on Wed, 7 May 2014 14:52:01 PMAll use subject to JSTOR Terms and Conditions

    http://www.jstor.org/action/showPublisher?publisherCode=rslhttp://www.jstor.org/stable/75363?origin=JSTOR-pdfhttp://www.jstor.org/page/info/about/policies/terms.jsphttp://www.jstor.org/page/info/about/policies/terms.jsp

  • S. Dijkgraaf (Discussion Meeting) S. Dijkgraaf (Discussion Meeting) with the swimbladder, is exclusively or better developed in the male. In other cases the sounds are only produced during mating or breeding activities. When such sounds were played back to silent fishes of the same species, a general activity increase and sometimes a positive approach towards the sound source (at close

    range) or towards fellow fishes was observed (Tavolga I958). In other cases the sound had obviously a threat function (Dijkgraaf 1947b). There are certainly many other possibilities like guarding the nest, defence of territory, and perhaps even echo-location (Griffin I958). More evidence is urgently needed, particularly with

    respect to the biological significance of hearing in freshwater fishes.

    REFERENCES (Dijkgraaf)

    Dijkgraaf, S. I947a Experientia, 3, 206-208. Dijkgraaf, S. 1947b Experientia, 3, 493-494. Dijkgraaf, S. I950 Physiol. comp. Oecol. 2, 81-106. Dijkgraaf, S. I952a Z. vergl. Physiol. 34, 104-122. Dijkgraaf, S. I952b Experientia, 8, 205-216. Dijkgraaf, S. & Verheijen, F. J. 1950 Z. vergl. Physiol. 32, 248-256. Fish, M. P. I954 Bull. Bingham Oceanogr. Coll. 14, 3-109. Frisch, K. v. I936 Biol. Rev. 11, 210-246. Frisch, K. v. 1938 Z. vergl. Physiol. 25, 703-747. Frisch, K. v. & Dijkgraaf, S. I935 Z. vergl. Physiol. 22, 641-655. Griffin, D. R. I958 Listening in the dark. New Haven. Poggendorf, D. I952 Z. vergl. Physiol. 34, 222-257. Pumphrey, R. J. I950 Symp. Soc. Exper. Biol. 4, 3-18. Reinhardt, F. I935 Z. vergl. Physiol. 22, 570-603. Schneider, H. I94I Z. vergl. Physiol. 29, 172-194. Sch6ne, H. 1959 Ergebn. Biol. 21, 161-209. Suckling, E. E. & Suckling, J. A. I950 J. gen. Physiol. 34, 1-8. Tavolga, W. N. I958 Physiol. Zool. 31, 259-271. Wohlfahrt, T. A. I939 Z. vergl. Physiol. 26, 570-604. Wohlfahrt, T. A. 1950 Z. vergl. Physiol. 32, 151-175.

    Some aspects of mammalian hearing under water

    By F. W. REYSENBACH DE HAAN

    Eindhoven, Holland

    In all probability the first, most primitive life must have had its origin in the water. When one tries to form an idea of the development of 'hearing under water', it is understandable that the formation of an adequate sensory apparatus for hearing depends on the development of the tactile sense, and later on the coming into

    being of a nervous system, lateral line organ, and finally on the formation of the stato-acoustic end-organs of the labyrinth. This gives little cause for wonder, as the reaction toOpressure waves must have been an early felt biological necessity. The step from pressure waves under water to sound waves of very low frequency is neither a great nor a fundamental step; it is merely the addition of sound modality to vibration.

    with the swimbladder, is exclusively or better developed in the male. In other cases the sounds are only produced during mating or breeding activities. When such sounds were played back to silent fishes of the same species, a general activity increase and sometimes a positive approach towards the sound source (at close

    range) or towards fellow fishes was observed (Tavolga I958). In other cases the sound had obviously a threat function (Dijkgraaf 1947b). There are certainly many other possibilities like guarding the nest, defence of territory, and perhaps even echo-location (Griffin I958). More evidence is urgently needed, particularly with

    respect to the biological significance of hearing in freshwater fishes.

    REFERENCES (Dijkgraaf)

    Dijkgraaf, S. I947a Experientia, 3, 206-208. Dijkgraaf, S. 1947b Experientia, 3, 493-494. Dijkgraaf, S. I950 Physiol. comp. Oecol. 2, 81-106. Dijkgraaf, S. I952a Z. vergl. Physiol. 34, 104-122. Dijkgraaf, S. I952b Experientia, 8, 205-216. Dijkgraaf, S. & Verheijen, F. J. 1950 Z. vergl. Physiol. 32, 248-256. Fish, M. P. I954 Bull. Bingham Oceanogr. Coll. 14, 3-109. Frisch, K. v. I936 Biol. Rev. 11, 210-246. Frisch, K. v. 1938 Z. vergl. Physiol. 25, 703-747. Frisch, K. v. & Dijkgraaf, S. I935 Z. vergl. Physiol. 22, 641-655. Griffin, D. R. I958 Listening in the dark. New Haven. Poggendorf, D. I952 Z. vergl. Physiol. 34, 222-257. Pumphrey, R. J. I950 Symp. Soc. Exper. Biol. 4, 3-18. Reinhardt, F. I935 Z. vergl. Physiol. 22, 570-603. Schneider, H. I94I Z. vergl. Physiol. 29, 172-194. Sch6ne, H. 1959 Ergebn. Biol. 21, 161-209. Suckling, E. E. & Suckling, J. A. I950 J. gen. Physiol. 34, 1-8. Tavolga, W. N. I958 Physiol. Zool. 31, 259-271. Wohlfahrt, T. A. I939 Z. vergl. Physiol. 26, 570-604. Wohlfahrt, T. A. 1950 Z. vergl. Physiol. 32, 151-175.

    Some aspects of mammalian hearing under water

    By F. W. REYSENBACH DE HAAN

    Eindhoven, Holland

    In all probability the first, most primitive life must have had its origin in the water. When one tries to form an idea of the development of 'hearing under water', it is understandable that the formation of an adequate sensory apparatus for hearing depends on the development of the tactile sense, and later on the coming into

    being of a nervous system, lateral line organ, and finally on the formation of the stato-acoustic end-organs of the labyrinth. This gives little cause for wonder, as the reaction toOpressure waves must have been an early felt biological necessity. The step from pressure waves under water to sound waves of very low frequency is neither a great nor a fundamental step; it is merely the addition of sound modality to vibration.

    54 54

    This content downloaded from 169.229.32.136 on Wed, 7 May 2014 14:52:01 PMAll use subject to JSTOR Terms and Conditions

    http://www.jstor.org/page/info/about/policies/terms.jsp

  • Some aspects of mammalian hearing under water

    Before, in a remote past, dramatic geological changes had created the conditions for the development of life on land and therefore also for life in the air, the fishes were the most highly developed vertebrates. They probably possessed a hearing organ entirely adapted and adjusted to hearing under water. We assume that some of these animals possessed the potency to answer with success the tremendous demands made by the transition to land life. Under-water hearing was transmuted into air-hearing. Air-hearing finally reached its highest degree of development in the mammals.

    However interesting this development may be, it lies outside the scope of this lecture. We wish only to call your attention to the behaviour of mammalian

    hearing, which is air-hearing par excellence, when it has to function under water. Which ways had nature to follow to readapt this kind of hearing with optimal

    results to the second change of environment? Was it a regression or a new step forward?

    It is known that there exists a series of mammalian species which have found their way back to aquatic life. These animals lead a life which is partially or entirely readapted to the water. In order to save time while still giving you a reasonable idea of some aspects of mammalian hearing under water, I propose to discuss only the possibilities of two mammalian hearing organs, one which is not at all, and another which is entirely adapted to hearing in this medium: on the one hand the

    hearing of man, on the other that of the toothed whale.

    Before we enter in detail into these problems, a few essential questions must be answered:

    (1) What is sound?

    (2) What is the biological significance of sound? Sound is a periodic compression and rarefaction of the medium in which it is

    produced, transmitting itself with a speed dependent on this medium, and which, from the biological point of view, may result in an acoustic sensation. We therefore

    speak of the sound wave, the sound frequency or pitch, the speed of sound and the intensity of sound.

    The mutual relationship between the first three is indicated by the equation

    A = v/v

    The wavelength of sound A is equal to the speed of sound v divided by the

    frequency v. The higher the frequency, the shorter the wavelength and the more the waves are bundled and obtain the nature of rays, as is the case with light. According to the above definition, the wavelength is, however, also dependent on the speed of sound, which in turn depends on the medium. In the air this

    velocity is about 300 m/s, in sea water 1200 m/s, or four times greater. A sound wave of the same frequency is therefore four times as long in water as in air