Re: How is possible for a sperm whale to dive to 1000 m ?

Hi there.

Pressure isn't really too much for the whale to cope with for a couple of 
simple reasons...

The whale takes a breath at atmospheric pressure, then dives. As the 
animal dives through deeper and deeper pressure, the air inside the lungs 
becomes DENSER, because of Boyle's law. Part of the whale contains tissues 
that are compressable (lungs, intenstines, holes in teeth etc.), the rest 
is incompressable (ie. bones, blood and solid organs). So all the air 
pockets in the whale gradually shrink as the animal decends as the air 
inside gets denser and denser (and gradually occupies less space).

So really, all the whale is limited by is the cold (but the blubber layer 
helps counteract this), and an eventual contraction of all the air filled 
spaces inside. Whales also need to swim around at depth, and the longer 
they stay down, the longer their hunting forays can be. Most diving 
mammals have adaptations to slow their pulse down (bradycardia) to enable 
them to use less oxygen during their dive. Whales also shunt oxygen 
around, have a higher haemoglobin count and numerous other interesting 
physiological adaptations.

check out  http://www.uwrf.edu/biology/electives_dir/444_dir/VSmith/Page1.html
for heaps of interesting info about whale physiology.

Hope this helps.

Regards,

Alastair