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From: arf@ddsw1.MCS.COM (Jack Schmidling)
Newsgroups: sci.bio,talk.environment
Subject: Bats by a Mile
Message-ID: <1991May17.044756.26698@ddsw1.MCS.COM>
Date: 17 May 91 04:47:56 GMT
Organization: ddsw1.MCS.COM Contributor, Wheeling, IL
Lines: 35


 
 Article 4431 (22 more) in sci.bio:
 From: mll@hpfcso.FC.HP.COM (Mark Luce)
 Subject: Sonar: Bats vs. Dolphins vs. Humans
 
 > I am interested in any comparisons of the sonar capabilities of bats,
 dolphins, and humans (human technology, of course!). In particular, I have
 heard the claim that bats and/or dolphins have certain sonar capabilities
 which we have not as yet been able to duplicate technologically. Is there
 any truth to this, or is this just another modern folk myth?
 ----------
 
 ARF says:
 
 Bats win by a wide margin.  In gross terms, electronic sonar can barely 
 detect a foot long fish.  A dolphin can find a golf ball with difficulty 
 after much forced training.  Bats, on the other hand, would starve to death 
 if they could not pursue and capture thousands of mosquito sized insects, on 
 the wing, every night.
 
 What gives bats the edge over dolphins is a much higher frequency.  
 Bats operate from audio to about 100 khz.  They alter not only the frequency 
 but the rep rate as they close on the target to maximize resolution.  
 Dolphins operate in the human audio range so the amount of data (resolution) 
 is much less but their normal food is much larger than insects.  High 
 frequency would also be absorbed much faster in water so the range would be 
 more limited.
 
 The above of course, only applies to insectivorous bats.  Many fruit eating 
 bats have no echo-location capabilities at all.
 
 arf