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No. 113: Sep-Oct 1997

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Acoustical Pipes In Beaked Whales?

Because they are relatively rare, the comings and goings of beaked whales remain largely unrecorded. These mammals are effectively toothless for predatory purposes. In fact, some marine biologists speculate that they secure their slippery prey by suddenly vacuuming them up by actuating a pumplike tongue. (AR#2)

But how do the beaked whales find their prey in the first place? With their sonar, of course. But these superbly streamlined animals lack the huge external ears of the sonar-using bats. How do they detect the weak echoes bouncing off fleeing fish?

P. Zioupos and J. Currey, at the University of York, have drawn attention to the rostrum bone that forms the beaklike upper jaw of Blaineville's beaked whale. At 2.7 grams/cubic centimeter, this bone is 50% denser than the average mammalian bone.

"The bone also turned out to have unique chemical properties. It contains 35 per cent calcium by weight -- 13 per cent more than the highest value known previously. Using microscopes, the team showed that the bone is riddled with tiny tunnels. containing highly concentrated minerals."

The channelled nature of this bone make it very brittle, making it unlikely that it is used as a ram in mating bouts. Zioupos and Currey propose that this uniquely structured bone is really an acoustical pipe for the beaked whales' sonar signals.

(Barnett, Adrian; "Do Whales Talk through Brittle Beaks?" New Scientist, p. 20, May 10, 1997.)

Comment. Acoustical pipes were also invented by close relatives of the beaked whales, the dolphins. With the dolphins, it is the lower jaw that has been converted into a "sound pipe" for receiving sonar echoes. Dugongs, too, possess squamosal bones filled with oil that are probably also connected with sound detection. Evolution has been highly innovative -- three times, in different ways -- in designing acoustical pipes in marine mammals! This is very impressive for a method that begins with a random process. More details in BMO7-X1 in Mammals II.

Strap-toothed whale This strap-toothed whale is one of the beaker whales. The teeth of this male prevent it from opening its mouth more than a couple of inches. Blaineville's beaked whale has two large, leaf-like teeth projecting upwards and forwards. These grotesque teeth are often covered with barnacles!

From Science Frontiers #113, SEP-OCT 1997. 1997-2000 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