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No. 43: Jan-Feb 1986

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Piscatorial Data Processing

Mammals such as bats and porpoises have their acoustical navigational gear, while many fish have opted for electrical methods of scanning their surroundings. The short-range "radars" of these fish are marvelously sophisticated, considering the low limb fish occupy on the Tree of Life. In fact, the following introductory paragraph from an article in Nature sounds almost as if it came from a textbook on electronic signal processing.

"Behavioural experiments have demonstrated that certain species of fish can perform remarkable analyses of the temporal structure of electrical signals. These animals produce an electrical signal within a species-specific frequency range via an electric organ, and they detect these signals by electroreceptors located throughout the body surface. In the context of one electrosensory behaviour, the jamming avoidance response (JAR), the fish Eigenmannia determines whether a neighbour's electric organ discharge (EOD), which is jamming its own signal, is higher or lower in frequency than its own. The fish then decreases or increases its frequency, respectively. To determine the sign of the frequency difference, the fish must detect the modulations in the amplitude and in the differential timing, or temporal disparity, of signals received by different regions of its body surface. The fish is able to shift its discharge frequency in the appropriate direction in at least 90% of all trials for temporal disparities as small as 400 ns."

(Rose, Gary, and Heiligenberg, Walter; "Temporal Hyperacuity in the Electric Sense of Fish," Nature, 318:178, 1985.)

Comment. ns = nanosecond = 10-9 second. There must be some chips in those fish! Sorry, couldn't resist that one.

From Science Frontiers #43, JAN-FEB 1986. 1986-2000 William R. Corliss

Science Frontiers Sourcebook Project Reviewed in:

Quotes

  • "A sourcebook of unexplained phenomena is therefore a valuable addition to a collection of scientific literature. William R. Corliss has provided this in the past with his source books of scientific anomalies in several subjects, and now he has provided it for astronomy. He has done an excellent job of collecting and editing a large amount of material, taken in part from scientific journals and in part from scientific reporting in the popular or semi-scientific press." -- "The Mysterious Universe: A Handbook of Astronomical Anomalies", reviwed by Thomas Gold, Cornell University, in Icarus, vol.41, 1980

  • "An interesting, systematic presentation of unusual weather [..] This book is recommended for a general audience" --"Corliss, William R., Tornados, Dark Days, Anomalous Precipitation, and Related Weather Phenomena, Sourcebook Project, 1983.", revieweed in Choice, September 1983
  • "..the science is necessarily somewhat speculative, but Corliss's symthesis is based on reputable sources." -- "Corliss, William R. (Compiler). Lightning, Auroras, Nocturnal Lights, and Related Luminous Phenomena" reviwed by Joseph M. Moran, Univ. of Wisconsin in Science Books and Films, Sep/Oct 1983

  • "Before opening the book, I set certain standards that a volume which treads into dangerous grounds grounds like this must meet. The author scrupulously met, or even exceeded those standards. Each phenomenon is exhaustively documented, with references to scientific journals [..] and extensive quotations" -- "Book Review: The moon and planets: a catalog of astronomical anomalies", The Sourcebook Project, 1985., Corliss, W. R., Journal of the Royal Astronomical Society of Canada, Vol. 81, no. 1 (1987), p. 24., 02/1987