"No Limit," the French
National Diving team demonstrates their remarkable skills
by "free diving" to incredible depths without the aid of oxygen.
One of their members, Loic Leferme, has set the world record
in this sport. Another Frenchman, Andy Le Sauce, has achieved
the world's longest breath-hold at seven minutes and thirty-five
seconds. Of course, these world records apply only to humans.
Marine mammals such as whales and dolphins are the world's
true deep dive champions. How do they do it?
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ancestors of today's marine mammals first got their feet wet
some 50 million years ago. Since then, a suite of adaptive
strategies has evolved to permit these air-breathing animals
to submerge for long periods of time. First, marine mammals
actually have more blood than their land-based relatives do.
Blood accounts for about 12 percent of an elephant seal's
bodyweight, compared to just 7 percent in humans. Plus, the
specialized blood chemistry of marine mammals allows them
to store oxygen more effectively.
this newborn Harbor Seal grows up, it will be able to
store roughly twice as much oxygen in its blood as this
example, harbor seals can store roughly twice as much oxygen
per 100 milliliters of blood than humans. But even these adaptations
combined can not account for the lengths of time marine mammals
can spend underwater. They must have other ways of conserving
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NOAA/Dept. of Commerce