pressure and dolphin escape question from Mr. Mahon's class

From: NAMMACETA@aol.com
Date: Sat Oct 28 2000 - 09:32:29 EDT


Ques: Why does pressure differences underwater not affect whales?

Ans: Whales fill their lungs with air before diving, but the pressure
compresses the air into a tiny "bundle". Then the increased pressure forces
the ribs to collapse inward (this also keeps the rib bones from fracturing
under pressure) onto the lungs, squeezing and compressing the lungs. This
squeeze, forces the air into pockets of the lung like the bronchi and
trachea, and the small bronchioles, and into air sacs near the blowhole
(nostril). The squeeze on the lungs reduces the flow of blood into the
lungs. This keeps air from the lungs from absorbing into the blood in great
quantities, and keeps nitrogen from absorbing in huge quantities. AS the
whale starts coming back up, and pressure is reduced, the process reverses
itself.

Ques: Why don't captured dolphins simply leap over the nets?

Ans: Great question. Probably because of the strength of the social bond
within the herds, panic and general confusion.

Take care

Scott



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