[extropy-chat] HISTORY: Solved & Unsolved Riddles

[Spike]

> 
> > 4. How can sperm whales hold their breath for half an hour 
> at a time,
> > descend into the abyss, and have fights to the death with 
> giant squid
> > and then surface without getting the bends or nitrogen narcosis? We
> > can't do that even with all our fancy diving gear unless we 
> mix helium
> > with our air supply and spend hours depressurizing... or can we?
> 
> Now that is a very interesting question -- my best bet would be that
> they have evolved to be tolerant nitrogen bubbles in the bloodstream.
> To the best of my knowledge there isn't a clear reason that nitrogen
> bubbles should be harmful (i.e. they aren't toxic in any way).


No wait, please disregard my previous post.  The reason
whales don't get the bends is that they are not actually
breathing while they are under water, the way human
scuba divers do.  They don't get nitrogen narcosis for
the same reason: they aren't carrying much nitrogen
to the depths.  

The reason they can hold their breath half an hour is
related to the square-cube law.  Compare your breathing
rate to that of a mouse, then scale linearly up to the 
size of a whale.  

spike