Subject: Whalesongs and acoustics

Martine Berube (mberube@ulb.ac.be)
Mon, 18 May 1998 16:47:49 +0200 (MET DST)

Dear Elizabeth,
I have pasted the abstract of a recent paper dealing with acoustics, I
thought it could be of some help.
In addition, you can look at this two websites:

http://www.zoology.ubc.ca/~adoption/sounds.html
http://elfi.com/csi97305.html

have a good day,
Martine
___________________
Au, W. W. L. and P. E. Nachtigall
1997
Acoustics of echolocating dolphins and small whales.
Marine Behavior & Physiology 29(1-4): 127-162.
   One of the most effective methods for an animal to probe an underwater
environment for the purpose of
navigation, obstacle and predator avoidance, and prey detection is by the
use of underwater sounds or
acoustic signals. Dolphins and small whales emit sounds and analyze
returning echoes to detect and
recognize objects underwater, a process referred to as echolocation. We will
first discuss the acoustic
reception system of dolphins and consider topics such as auditory
sensitivity, spectral analysis capabilities
and directional hearing. We will then focus on the acoustic transmission
system of dolphins, discussing topics
such as properties of echolocation signals and propagation of the
echolocation signals from the animals' head.
Dolphins echolocate by emitting high intensity broadband acoustic pulses in
a directional beam and listening
to echoes reflected from objects in their environment. Echolocation studies
on three species, the Atlantic
bottlenose dolphin (Tursiops truncatus), white whale (Delphinaterus leucas),
and false killer whale (Pseudorca
crassidens) have been conducted extensively in Kaneohe Bay, Oahu, Hawaii.
Measurements of dolphin
echolocation signals in the open waters of Kaneohe Bay indicate that the
signals are of short duration (less
than 50-70 mu s), high intensity (up to 230 dB re 1 mu Pa peak-to-peak),
broadband (30-40 kHz 3-dB bandwidth)
and of high frequency (peak frequencies between 100 and 130 kHz). Evidence
indicates that the frequency of
the signals may be controlled by intensity, with high intensity signals
having high peak frequencies.
Echolocation signals are emitted in a beam that is directed forward in the
horizontal plane for Tursiops and
Delphinapterus, upwards at an angle of 5 to 10 degrees in the vertical
plane. The vertical beam of Pseudorca is
directed between 0 degrees and -5 degrees downward. All three species use a
pulse mode of transmission in
which the repetition rate of the signal is adjusted so that the desired
echoes are received before another pulse
is transmitted. 
_____________________


At 07.16 PM 17-05-1998 PDT, you wrote:
>
>Could you please help me...I have a project due in my Biology 101 class 
>due on whale songs?  Could you give me some basic information about 
>whale songs and if possible any web sites dealing with whale songs?  
>Thanks for your help.
>
>Elizabeth Barkovich
>Converse College 2001
>Spartanburg, SC, USA
>
>______________________________________________________
>Get Your Private, Free Email at http://www.hotmail.com
>
>
Martine Berube
Unit of Evolutionary Genetics
Department of Molecular Biology
Free University of Brussels (ULB)
CP 244
Bld du Triomphe
B-1050 Brussels, Belgium
Tel: +32 2 650 5427
Fax: +32 2 650 5421
Email: mberube@ulb.ac.be