From: Pieter Arend Folkens (animalbytes@earthlink.net)
Date: Thu Feb 15 2001 - 03:25:25 EST


>Why do whales not experience deep compression sickness?

I think what you refer to is the bends, caused when gas bubbles expand as
scuba divers rise to the surface.

Going down is not a problem for divers or whales as the body compresses
under the water pressure at depth. If humans went way down, they might
break some ribs as the pressure crushes the rib cage. This does not happen
to the deep diving whales, as their rib cage is hinged so the ribs can
rotate inward as the viscera compresses under pressure.

One the way up, scuba divers have breathed compressed air into their bodies
via the scuba tanks. As they rise and the pressure is reduced, the gas
bubbles in their bodies expand, causing the deadly "bends." To compensate
for this, a scuba diver must rise slowly, and stop in stages if the dive
was particularly deep.

Whales do not experience this because they do not breath compressed air at
depth. The air they take in is compressed naturally on the way down and
expands on the way up back to normal.

It is the intake of air at depth that expands upon rising that causes human
scuba divers problems.


Pieter Folkens

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