Re: [sauropod@berkeley.edu: Re: [mhabib5@jhmi.edu: Re: sauropod lung collapse]]

[Michael Habib <mhabib5@jhmi.edu>]

> I believe diving birds exhale as much as they can before they go down. 
> I
> think they probably have to, otherwise they wouldn't _go_ down...

Actually, penguins dive upon inspiration, so they're going down with a 
full tank (despite having to fight buoyancy).  See: Sato et al. 2002. 
The Journal of Experimental Biology 205, 1189–1197 (2002)

I cannot speak for loons, grebes, alcids, etc. but I suspect that they 
all go down with significant air storage (if not full tanks).  Diving 
ducks, for example, spend most of their energy (at least early in the 
dive sequence) to fighting Buoyancy (Vogel, 2003).

Ironically, penguins (which probably have the lowest buoyancy among 
diving birds) also have the most efficient propulsion.  The high 
buoyant divers are largely drag-based paddlers, so they're working very 
hard indeed.


Cheers,

--Mike Habib