You asked how whales can hold their breath for so long. They can do
this for a couple of reasons. First, they have very efficient lungs.
the lungs actually arent that large - if you look at them as a fraction
of their body size, they smaller than you'd expect (relative to people,
although of course in actual size they're much bigger). Secondly,
whales exchange a lot more air with each breath than we do - each whale
breath involves around 80-90% of the lung capacity being exchanged,
which is much more efficient than we can manage.
But one of the big reasons that whales can hold their breath for so long
is that they store a lot more oxygen in their muscles than we do. We
can do this too, but a whale's muscles have several times more oxygen in
them than ours. That way they can keep working on long dives.
The best divers, by the way, are sperm whales. They can stay down for
as long as two hours in some cases.
Phillip J. Clapham, Ph.D. Large Whale Biology Program Northeast Fisheries Science Center 166 Water Street Woods Hole, MA 02543, U.S.A.
tel. 508 495-2316 fax 508 495-2066 email: firstname.lastname@example.org
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