I'll not comment on which bird can hold it's breath longest, but I do recall
hearing about the deep diving feats of the larger penguins.
As I recall, these penguins, like whales, are able to collapse their rib
cage and lungs to a certain extent. This would have a number of purposes.
I can think of three.
1. Reduces physical damage due to increase water pressure during deep dive.
2. Reduced volume per mass would aid overcoming bouyancy for diving.
3. I'm trying to decide if the reduced gas volume in the 'collapsed' lungs
would help with reducing the partial pressure of CO2. I'll try to explain
it in human terms. When free diving for a long period or deep depth (ie
snorkelling), rather than trying to hold your breath you should exhale as
you get to your breath holding limit. This action removes the (more than
usual) CO2 concentrated air in your lungs. It is not lack of oxygen that
causes the inhale response that gives you a lung-ful of water, but the buld
up of CO2 in the bloodstream. By *exhaling* this CO2 imbalance is partially
alleviated, which buys you a little more time. I can only hazard that the
same technique would be used by deep/long diving mammals and birds.
Please note that the above is from memory, brobably clouded by oxygen
deprivation and stand to be corrected. Well sit down, actually I'm feeling
a little dizzy.
Andrew Peter Taylor wrote:
> Pat Macwhirter wrote:
> > >or which bird can hold its breath the longest....
> > Can anyone tell us which bird does hold its breath the longest and how the
> > physiology works?
> > I have a feeling the right answer is either the King Penguin or Emperor
> > Penguin, which I recall deep-dive to remarkable depths and must
> therefore require a long period where they do not breathe.
--
Eric Hocking "A closed mouth gathers no feet."
:: Melbourne, Australia ::
Remove "nospam." from address to email.
http://www.ozemail.com.au/~ehocking/
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