Dolphins produce various types of sounds in a wide range of frequencies. Characteristics of some sounds till now have not been correctly registered, that influenced on interpretation of their functions. Studying of the characteristics and functions of dolphins’ acoustical signals is the purpose of the present work. In this work the acoustical signals of two dolphins (Tursiops truncatus) were registered by two-channel system in the frequencies band up to 200 kHz at quasi-stationary position of the dolphins. The dolphins along with whistles are producing the packs of coherent and non-coherent broadband pulses. The waveform and spectrum of coherent pulses was invariable within a pack, but considerably varies from a pack to a pack. The waveform of each non-coherent pulse vary from a pulse to a pulse in each pack, therefore their spectrum also vary from a pulse to a pulse and have many extremums in the band of 6 - 200 kHz. It is very likely that the non-coherent pulses play a part of phonemes of a dolphin spoken language and the probing signals of dolphin’s non- coherent sonar. The use possibility of the signals by dolphins for communication and orientation was considered, as the signals apparently are bimodal. Results of the work have significance for further studying of the dolphin’s sonar and spoken language.
R. Kellogg, “A Review of the Archaeoceti,” Carnegie Institution of Washington Publication, Washington, D.C., No. 482, 1936, pp. 1-366.
L. G. Barnes, and E. Mitchell, “Cetacea,” In: V. J. Maglio and H. B. S. Cooke, Eds., Evolution of African Mammals Harvard University Press, Cambridge, 1978, pp. 582-602.
R. E. Fordyce, “Whale Evolution and Oligocene Southern Ocean Environments,” Paleogeography, Paleoclimatology, Paleoecology, Vol. 31, 1980, pp. 319-336. doi:10.1016/0031-0182(80)90024-3
P. D. Gingerich, N. A. Wells, D. E. Russell and S. M. I. Shah, “Origin of Whales in Epicontinental Remnant Seas: New Evidence from the Early Eocene of Pakistan,” Science, Vol. 220, No. 4595, 1983, pp. 403-406.
S. Leatherwood, R. R. Reeves, W. F. Perryn and W. E. Evans, “Whales, Dolphins, and Porpoises of the Eastern North Pacific and Adjacent Waters,” NOAA Technical Report NMFS Circular, Vol. 444, 1982, pp. 1-245.
W. A. Watkins, and D. Wartzok, “Sensory Biophysics of Marine Mammals,” Marine Mammal Science, Vol. 1, No. 3, 1985, pp. 219-260.
G. S. Miller, “The Telescoping of the Cetacean Skull,” Smithsonian Misc Coll. No. 76, 1923, pp. 1-67.
V. A. Ryabov, “Mechanisms of a Dolphin’s Echolocation Hearing,” In: S. Dible, P. Dobbins, J. Flint, E. Harland and P. Lepper, Eds., (Bio-Acoustics 2007), Proceedings of the Institute of Acoustics, Vol. 29, No. 3, 2007, pp. 283-293.
V. A. Ryabov, “Acoustic Clutter Field and Echo Reception by the Dolphin,” Biophysics, Vol. 53, No. 3, 2008, pp. 237-242.
V. A. Ryabov, “Role of the Mental Foramens in Dolphin Hearing,” Natural Science, Vol. 2, No. 6, 2010, pp. 646- 653.
V. A. Ryabov, M. A. Polyakov and N. G. Bibikov, “Characterization of Beam Patterns of Bottlenose Dolphin in the Transverse Plane,” Biophysics, Vol. 56, No. 3, 2011, pp. 529-534.
S. H. Ridgway, “Physiological Observations on the Dolphin Brains,” In: R. J. Schusterman, J. Thomas and F. G. Wood Eds., Dolphin Cognition and Behavior, a Comparative Approach, Erlbaum, Hillsdale, 1986, pp. 31-59.
J. C. Lilly and A. M. Miller, “Sounds Emitted by the Bottlenose Dolphin,” Science, Vol. 133, No. 3465, 1961, pp. 1689-1693.
M. C. Caldwell and D. K. Caldwell, “Intraspecific Transfer of Information via the Pulsed Sound in Captive Odon- tocete Cetaceans,” In: R. G. Busnel Ed., Animal Sonar Systems: Biology and Bionics, Laboratoire de Physiologie Acoustic, Jouy-en-Josas, France, 1967, pp. 879-936.
P. Tyack, “Patterns of Vocalization in Wild Tursiops Truncates,” Senior Thesis, Rockefeller University, 1976.
L. M. Herman, and W. N. Tavolga, “The Communication Systems of Cetaceans,” In: L. M. Herman, Ed., Cetacean Behavior: Mechanisms and Functions, Wiley Interscience, New York, 1980, pp. 149-209.
A. N. Popper, “Sound Emission and Detection by Delphinids,” In: L. M. Herman, Ed., Cetacean Behavior: Mechanisms and Functions, Wiley-Interscience, New York, 1980, pp. 1-52.
S. M. Brownlee, “Correlations between Sounds and Behavior in Wild Hawaiian Spinner Dolphins (Stenella longirostris),” Masters Thesis, University of California Santa Cruz, 1983.
S. M. Dawson, “Clicks and Communication: The Behavioural and Social Contexts of Hector’s Dolphin Vocalizations,” Ethology, Vol. 88, No. 4, 1991, pp. 265-276.
D. L. Herzing, “Vocalizations and Associated Underwater Behavior of Free-Ranging Atlantic Spotted Dolphins, Stenella Frontalis and Bottlenose Dolphin, Tursiops Truncatus,” Aqua Mammal, Vol. 22, 1996, pp. 61-79.
M. H. Rasmussen and L. A. Miller, “Whistles and Clicks from White-Beaked Dolphins, Lagenorhynchus Albirostris, Recorded in Faxaflo′i Bay, Iceland,” Aqua Mamm, Vol. 28, 2002, pp. 78-89.
M. O. Lammers, W. W. L. Au and D. L. Herzing, “The Broadband Social Acoustic Signaling Behavior of Spinner and Spotted Dolphins,” Journal of the Acoustical Society of America, Vol. 114, No. 3, 2003, pp. 1629-1639. doi:10.1121/1.1596173
M. O. Lammer, M. Schotten and W. W. L. Au, “The Spatial Context of Free-Ranging Hawaiian Spinner Dolphins (Stenella Longirostris) Producing Acoustic Signals,” Journal of the Acoustical Society of America, Vol. 119, No. 2, 2006, pp. 1244-1250. doi:10.1121/1.2151804
W. W. L. Au, “The Sonar of Dolphins,” Springer-Verlag, New York. 1993.
J. C. Lilly, “Distress Call of the Bottlenose Dolphin: Stimuli and Evoked Behavioral Responses,” Science, Vol. 139, 1963, pp. 116-118.
J. J. Dreher and W. E. Evans, “Cetacean Communication,” In: W. N. Tavolga, Ed., Marine Bioacousics, Pergammon Press, Oxford, Vol. l, 1964, pp. 373-399.
M. C. Caldwell, D. K. Caldwell and P. L. Tyack, “Review of the Signature-Whistle Hypothesis for the Atlantic Bottlenose Dolphin,” In: S. Leatherwood and R. R. Reeves, Eds., The Bottlenose Dolphin, Academic Press, San Diego, 1990, pp. 199-234.
V. M. Janik, “Whistle Matching in Wild Bottlenose Dolphins Tursiops Truncates,” Science, Vol. 289, No. 5483, 2000, pp. 1355-1357.
M. H. Rasmussen, M. Lammers, K. Beedholm and L. A. Miller, “Source Levels and Harmonic Content of Whistles in White-Beaked Dolphins (Langenorhinchus Albirostris),” Journal of the Acoustical Society of America, Vol. 120, No. 1, 2006 pp. 510-517. doi:10.1121/1.2202865
C. D. Hockett, “The Origin of Speech,” Scientific American, Vol. 203, 1960, pp. 99-196.
L. M. Herman, D. G. Richards and J. P. Wolz, “Comprehension of Sentences by Bottlenosed Dolphins,” Cognition, Vol. 16, No. 2, 1984, pp. 129-219.
L. M. Herman, “Cognition and Language Competencies Of Bottlenosed Dolphins,” In: R. J. Schusterman, J. Thomas and F. G. Wood, Eds., Dolphin Cognition and Behavior: A Comparative Approach, Lawrence Erlbaum Associates, Hillsdale, 1986, pp. 221-251.
L. M. Herman, “What Laboratory Research has Told Us about Dolphin Cognition,” International Journal of Comparative Psychology, Vol. 23, 2010, pp. 310-330.
L. M. Herman and W. R. Arbeit, “Frequency Difference Limens in the Bottlenose Dolphin: 1-70 kHz,” Journal of Auditory Research, Vol. 12, 1972, pp.109-120.
D. W. Jacobs, “Auditory Frequency Discrimination in the Atlantic Bottlenose Dolphin, Tursiops Truncatus Montague. A Preliminary Report,” Journal of the Acoustical Society of America, Vol. 52, No. 2B, 1972, pp. 696-698.
R. K. R. Thompson, and L. M. Herman, “Underwater Frecuency Discrimination in the Bottlenosed Dolphin (1-140khz) and Human (1-8khz),” Journal of the Acoustical Society of America, Vol. 57, 1975, pp. 943-948.
T. H. Bullock, A. D. Grinell, E. Ikezono, K. Kameda, J. Katsuki, M. Nomota, O. Sato, N. Suga and K. Yanagisawa, “Electrophysiological Studies of Central Auditory Mechanisms in Cetaceans,” Zeitschrift fiir Vergleichende Phvsiologie, Vol. 59, 1968, pp. 117-156.
C. S. Johnson, “Auditory Masking of One Pure Tone by Another in the Bottlenosed Porpoise,” Journal of the Acoustical Society of America, Vol. 49, No. 5, 1970, pp. 1317-1318.
L. M. Herman, P. Morrel-Samuels and A. A. Pack, “Bottlenosed Dolphin and Human Recognition of Veridical and Degraded Video Displays of an Artificial Gestural Language,” Journal of Experimental Psychology: General, Vol. 119, 1990, pp. 215-230. doi:10.1037/0096-3445.119.2.215
C. S. Johnson, “Masked Tonal Threshold in the Bottlenose Porpoise,” Journal of the Acoustical Society of America, Vol. 44, No. 4, 1968, pp. 965-967. doi:10.1121/1.1911236
C. S. Johnson, M. W. McManus and D. Skaar, “Masked Tonal Hearing Thresholds in the Beluga Whale,” Journal of the Acoustical Society of America, Vol. 85, No. 6, 1989, pp. 2651-2654.
W. W. L. Au and P. W. B. Moore, “Critical Ratio and Critical Bandwidth for the Atlantic Bottlenose Dolphin,” Journal of the Acoustical Society of America, Vol. 88, No. 3, 1990, pp. 1635-1638. doi:10.1121/1.400323
V. V. Popov, A. Y. Supin and V. O. Klishin, “Frequency Tuning of the Dolphin’s Hearing as Revealed by Auditory Brain-Stem Response with Notch-Noise Masking,” Journal of the Acoustical Society of America, Vol. 102, No. 6, 1997, pp. 3795-3801.
L. Rendell and H. Whitehead, “Culture in Whales and Dolphins,” Behavior and Brain Science, Vol. 24, No. 2, 2001, pp. 309-382.
M. Kruetzen, J. Mann, M. Heithaus, R. Connor, L. Bejder and W. B. Sherwin, “Cultural Transmission of Tool Use In Bottlenose Dolphins,” Proceedings of the National Academy of Sciences of the United States of America, Vol. 105, No. 25, 2005, pp. 8939-8943.
D. F. Bjorklund and J. M. Bering, “Big Brains, Slow Development, and Social Complexity: The Developmental and Evolutionary Origins of Social Cognition,” In: M. Bru¨ne, H. Ribbert and W. Schiefenho¨vel, Eds., The Social Brain: Evolutionary Aspects of Development and Pathology, Wiley, New York, 2003, pp. 133-151.
D. L. Herzing, “Transmission Mechanisms of Social Learning in Dolphins: Underwater Observations of Free- Ranging Dolphins in the Bahamas,” In: F. Delfour and M. J. Dubois, Eds., Autour de l’ethologie et de la Cognition Animale, Presses Universitaires de Lyon, Lyon, 2005, pp. 185-194.
C. E. Bender, D. L. Herzing and D. F. Bjorklund, “Evidence of Teaching in Atlantic Spotted Dolphins (Stenella frontalis) by Mother Dolphins Foraging in the Presence of Their Calves,” Animal Cognition, Vol. 12, No. 1, 2008, pp. 43-53.
D. L. Renaud and A. N. Popper, “Sound Localization by the Bottlenose Porpoise Tursiops Truncates,” The Journal of Experimental Biology, Vol. 63, No. 3, 1975, pp. 569-585.
B. K. Branstetter, S. J. Mevissen, L. M. Herman, A. A. Pack and S. P. Roberts, “Horizontal Angular Discrimination by an Echolocating Bottlenose Dolphin Tursiops Truncates,” Bioacoustics, Vol. 14, No. 1, 2003, pp. 15- 34.
B. K. Branstetter and E. Mercado III,, “Sound Localization by Cetaceans,” Journal of Comparative Psychology, Vol. 19, 2006, pp. 26-61.
W. E. Evans, “Vocalizations among Marine Mammals,” In: W. N. Tavolga, Ed., Marine Bioacoustics, Pergamon Press, New York, Vol. 2, 1967, pp. 159-186.
M. O. Lammers and W. W. L. Au, “Directionality in the whistles of Hawaiian Spinner Dolphins Stenella Longirostris: A signal Feature to Cue Direction of Movement,” Marine Mammal Science, Vol. 19, No. 2, 2003, pp. 249- 264.
Z. Reznikova, “Analytical Review of Temporal Methodological Approach to the Study of Animal Language Behavior,” In: A.D. Koshelev and T. V. Chernigovskaya, Eds., Language and Reasoning. Volume I. Animal Communication and Human Language, Language Origins. Language of Slavonic Cultures, Moscow, 2008, pp. 293- 337.