Subject: Whale breathing

Mike Williamson (m.dalebout@auckland.ac.nz)
Sat, 20 Sep 1997 2:11:25 GMT+1200

Dear Mitch, 

You asked how a whale's blowhole was connected to its lungs.

The nasal passage (1 in toothed whales, 2 in baleen whales) comes down from 
the blow hole and passes into the skull via an opening known as the bony nares 
This is similar to the hole we have in our skull where our nasal passages enter.
The nasal passage joins up with the trachea which leads to the lungs.

You also enquired whether whales and dolphins can breathe through their mouths.
Looking at E. J. Slijper's book, 'Whales' (1979) which is a veritable treasure 
chest of information on whale biology, it would appear that baleen whales
can breathe through their mouths if they wanted to (although would rarely have
the opportunity as a whale's mouth is usually under the water) as the structure
of their larynx and pharynx does not really differ from that of terrestial
mammals. In toothed whales however, the larynx is shaped in such a way that
it provides complete separation between the air and food passages.  This would
imply that toothed whales like dolphins in contrast to baleen whales
are not able to breathe through their mouths. If every part of the larynx 
was completely relaxed, a tiny bit air might just be able to squeeze through,
but mouth breathing for odontocetes would at best be very very difficult,
and would never supply the animal with even a fraction of its
oxygen requirement.

Hope this answers your questions
Have a fantastic time at Sea World!

cheers

Merel
***********************************
Ms. Merel Dalebout
Ecology & Evolution Research Group
Thomas Building, Level 1
School of Biological Sciences
University of Auckland
Private Bag 92-019
Wellesley Street
Auckland, N.Z.
Ph:09-373-7599 ext. 4588
Fax: 09-373-7417
e-mail: m.dalebout@auckland.ac.nz