Whale adaptations to environment

From: Peter M Scheifele (acousticp2@juno.com)
Date: Sat Dec 02 2000 - 20:49:52 EST


> Do you think you could give me species examples which
> have a physiological or behavioural adaptation that relates directly
> to habitat?

Richard

Great to hear from you! As a bioacoustician I can tell you that there
appears to be an audiological adaptation among cetaceans which is now
under investigation by myself and my colleagues (and especailly Dr.
Darlene Ketten at Woods Hole). Here it is:

When we investigate the hearing abilities of whales we are tending to
find that species that inhabit very coastal (and river) waters such as
river dolphins and Harbour Porpoise, have hearing ranges that include
much higher frequencies than others. Example: The Harbour Porpoise
(Phocoena phocoena) has a hearing range from 1 kHz through 150 kHz (and,
incidentally, a vocal range as well). Now, in comparison, more pelagic
species of odontocetes such as Beluga and Pilot Whales have lower hearing
ranges. Example: the Beluga range of hearing (and vocalisation) is from
100 Hz through 120 kHz at best. We currently believe that this is due to
the turbidity that the more coastal, less pelagic species have to work in
for the purpose of finding food.

In stark comparison, mysticetes are browsers and have no need of
echolocation abilities and this implies more of a need for widely
distributed groupings of animals. The consequence, acoustically, is the
lack of high frequency hearing and sound production but the development
of low frequency communication phonations and hearing abilities.
Example: Fin whales range fo hearing an sound production (we think,
based upon its phonations) is between 18 Hz and 1 kHz.

A possible exception may be the Blue Whale (again this is only conjecture
at the moment but is debated) whose distribution might just be in herds
whose "pod area" could be tens or more of kilometers. It might just be
that the Blue Whale uses a very low frequency form of echolocation as an
aid to navigation to traverse deep ocean areas and get around sea mounts,
etc..

Does this help at all? Let me know.
Best Regards,
Peter

Peter M."Skip" Scheifele LCDR USN (Ret.)
Director of Bioacoustic Research, University of Connecticut NURC NA&GL
(Voice) 860-405-9103/9121; acousticp2@juno.com;
scheifel@uconnvm.uconn.edu
www.nurc.uconn.edu
http://ap.nurc.uconn.edu/cos/



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