Re: lung capacity

[Dann Pigdon <dannj@alphalink.com.au>]

Dann Pigdon wrote:
>
> Indeed. Diving animals can further complicate the issue. Aquatic
> varanids can have quite complex, convoluted lungs, as compared to the
> simple bag-like organs in other varanid species. Perhaps it is the
> internal surface area of the lungs, rather than absolute volume, that is
> a better indicator of aerobic capacity.
> 
> Also, lung capacity doesn't necesarily indicate metabolic level. Aquatic
> varanids don't have higher metabolic rates than their landlubber
> cousins. They can just go longer between breaths.

Just a slight correction, after doing more varanid research.

Although the lungs of aquatic varanids ARE more complex than those of
most non-aquatic species, the most convoluted lungs belong to V.
salvadori (Salvador's monitor). It is a largely arborial species that
doesn't seem to spend much time (if any) under water. Some researchers
also think it may have inherited its complex lung structure from a much
larger ancestor.

Being an active predator, it's convoluted lungs allow it quick bursts of
high metabolic activity, followed by quick recovery times. The original
question regarding this thread was whether the size of the ribcage
indicates the volume of the lungs. Since varanids with complex lung
structures vary little skeletally from those with simple lizard-like
lungs, then the answer (at least for non-mammals) seems to be "no".

-- 
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Dann Pigdon                   Australian Dinosaurs:
GIS / Archaeologist         http://www.geocities.com/dannsdinosaurs
Melbourne, Australia        http://www.alphalink.com.au/~dannj/
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