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Re: feathers as N2 excretors




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Message text written by INTERNET:larryf@capital.net

"I haven`t read Reichholf, but as far as an ecological, and evolutionary
reason as to why this might have happened, perhaps these "protobirds" took
to an arboreal enviorn to escape competition and predation from other
species on the ground. I imagine water might be scarce, (at least not
regularly available) in the arboreal enviornment. To seek it on the ground
would engender risk from predators. Those which could do without the
longest
would tend to survive to produce offspring."


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        While this does sound like a good argument on the surface, it's not
quite so good underneath because it assumes that birds (and "protobirds")
required a standing body of water to obtain water, when this isn't
necessarily true.  I'm not terribly knowledgeable about modern birds, so I
don't know how well this applies, but I know that many living animals,
including some reptiles and mammals, rarely if ever drink standing water --
they instead extract all the water they need from their diet (of both
plants and animals); others do drink, but subsist on dew, rain, etc.
collecting on other bodies (this seems to be particularly true of small,
arboreal herps, as an old pet anole showed me!)  

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                     Jerry D. Harris
                 Fossil Preparation Lab
          New Mexico Museum of Natural History
                   1801 Mountain Rd NW
               Albuquerque  NM  87104-1375
                 Phone:  (505) 899-2809
                  Fax:  (505) 841-2866
               102354.2222@compuserve.com