Re: Dinosaur urine?

[Patrick Norton <ptnorton@suscom-maine.net>]

Dan Pigdon wrote:

> That depends on whether the system found in birds is an adaptation to 
> flight
> or not. Excreting a paste in flight would seem to be easier than urinating 
> or
> passing solids, and being able to squirt it out at speed no doubt helps
> prevent feathers being fowled.

What is the evidence that this is a flight adaptation? Birds process waste 
very differently than flying mammals. For example, birds excrete nitrogenous 
waste from the blood as uric acid rather than urea dissolved in urine and 
eliminate all wastes through a single vent.  These are big differences. I'm 
speculating, but the *paste like" results from the bird system would seem to 
be more fundamental to the basic avian physiology than to adaptations for 
flight, per se. Interesting question though. Any evidence of combined uric 
acid and fecal secretions from coprolites attributed to derived theropods?

PTN