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Re: Morgan Tears 3.
Phillip Bigelow (n8010095@cc.wwu.edu)
6 Nov 1995 16:23:25 -0800
jamesb@hgu.mrc.ac.uk writes:
>Alex Duncan <aduncan@mail.utexas.edu> wrote:
>>
>>
>>Elephants have a functional mechanism for the transmission of low
>>frequency sound. It is not sonar.
>>
jamesb@hgu.mrc.ac.uk asked:
>Do you have an explanation why they have this?
Low frequency sound travels more efficiently in water OR in air than does
high frequency sound. Elephants use low frequency bellows and grunts to
signal their herd, call for mates, challenge rivals...all at long-distance,
if necessary.
Dr. David Weishampel has studied the nasal structure of duckbill dinosaurs
and has come to the conclusion that the convoluted air passageways found in
their skulls makes an ideal medium for producing low-frequency, long-range
sounds.....on land. If the duckbill tried to bellow while it's head were
submerged, it would succeed at only blowing a lot of bubbles.
The mechanism for low-frequency sound is entirely different in cetaceans,
which produce the majority of their sounds in the front, fat-filled part of
the skull called the "mellon". In the large mysticeti whales, at least, the
reflected-back (received) sounds are absorbed by the mandibles (the jaws,
folks), which transmit the sound to the jaw joint and thence to the auditory
bullae (the ear bones). Land-locked elephants don NOT have any of these
cetacean apomorphies. Sorry.
<pb>
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