Subject: Blowholes

Phil Clapham (phillip.clapham@noaa.gov)
Tue, 19 Jan 1999 07:19:30 -0500

Hi:

Thanks for the question about blowholes.  A whale's blowholes are
basically its nose.  They're used to breathe through when the whale
comes up to the surface for air.

Toothed whales (like dolphins and porpoises) have a single blowhole,
while baleen whales (like humpback and blue whales) have two.

The muscles around the blowholes are very strong, and clamp the
blowholes shut when the whale is underwater so that no water gets in. 
One other interesting thing about whales is that they are what we call
"voluntary" breathers - that is, they choose when to breathe rather than
breathing automatically (without thinking about it) the way we do.  this
is what you'd expect for a diving animal - they can't very well be
breathing underwater!

Hope this helps.

Phil Clapham

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Phillip J. Clapham, Ph.D.
Northeast Fisheries Science Center
166 Water Street
Woods Hole, MA 02543

tel (508) 495-2316
fax (508) 495-2066
Internet: phillip.clapham@noaa.gov