Animal Sonar Systems

Volume 28 of the series NATO Advanced Study Institutes Series pp 239-249

Electromyographic and Pressure Events in the Nasolaryngeal System of Dolphins during Sound Production

  • S. H. RidgwayAffiliated withNaval Ocean Systems Center
  • , D. A. CarderAffiliated withNaval Ocean Systems Center
  • , R. F. GreenAffiliated withNaval Ocean Systems Center
  • , A. S. GauntAffiliated withDepartment of Zoology, Ohio State University
  • , S. L. L. GauntAffiliated withDepartment of Zoology, Ohio State University
  • , W. E. EvansAffiliated withHubbs-Sea World Research Institute

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In electromyography fine wires are inserted into muscles to measure their activity periods. We have employed this technique to evaluate the activity of various muscles of the nasolaryngeal system of dolphins during the production of sounds. The anterior internus, the posterior internus, diagonal membrane muscle and the nasal plug muscle have been studied in greatest detail. These muscles fire just before and during the production of sounds whereas the hyoepi-glottal muscle and the intercostal muscles do not. Simultaneous video recordings of blowhole movement and electromyogram (EMG) have been made to correlate such movement with EMG and sound production.