Subject: Re: water pressure and whales

Al Romero (aromero@ACC.FAU.EDU)
Fri, 11 Apr 1997 08:45:58 -0500 (EST)

At 01:10 PM 4/10/97 -0400, you wrote:
>We get crushed by the enormous water pressure as we dive a relatively short
distance into the ocean.  How can whales dive up to 2 miles (sperm) and not
suffer the effects of water pressure?
Dear Friend:

The chest of deep diving cetaceans is very flexible and the diaphragm is set
very obliquely so that the weight of the abdominal viscera against it  on
one side makes the lung on the other side collapse.  When a cetacean is
returning to the surface, its lungs gradually expand and the nasal plug that
closes the blowholes is force open, projecting hot air with high levels of
humidity that in contact with the cooler air of the environment is
condensed.  This leads the casual observer to believe that the whale is
actually flushing water.

So instead of development a mechanism to avoid the collapse of their lungs,
these cetaceans have adapted to that fact.  High volume of blood and other
physiological adaptations help them to overcome great water pressures.

If you have any other questions, please do not hesitate to contact me again.

Best wishes,

Aldemaro Romero, Ph.D.		
Florida Atlantic University	(954)236-1125	
College of Liberal Arts		(954)236-1150 (F)
Department of Biology
2912 College Ave.,
Davie, FL 33314