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Re: Herbivorous Dinosaurs of the World ?



>I still haven't heard a reasonable explanation of what the animal would be
>doing with those big, feathered forelimbs during the 99% of its life when it
>>wasn't< brooding its eggs. If the wings evolved >solely< for brooding, they
>would just hang there uselessly the rest of the time, right? How about--the
>feathered forelimbs evolved for >something else<, and were, perhaps, useful
>for brooding eggs on those occasions when brooding needed to be done.

If feathers (or some feathers) were only of use during brooding, and if this
activity were restricted to certain seasons, I would have expected that they
would be lost through moult during the rest of the year (very much as many
modern birds lose specialized display plumes outside the breeding season).  As
feathers, once damaged, cannot be repaired, moult ensures a fresh set at the
start of the new season.

However, I would add that in modern birds wing-feathers are only rarely
used in
brooding, and then only in extreme situations in birds that nest in open, hot
areas (I believe stonecurlews are an example).  Most birds actually LOSE
feathers in order to develop a "brood patch" on the belly.  Sandgrouse, which
are desert nesters, have specialized breast feathers that can take up water by
capillary attraction; this is used to cool the eggs.  So unusual is
wing-brooding in birds that I find it hard to imagine this having been a major
factor in their evolution; if a non-locomotor function drove feather
evolution,
I would a priori favour thermoregulation (for contour feathers or for whatever
Sinosauropteryx has) or display (for larger feathers such as those on the arms
and tail of Caudipteryx), or both.
--
Ronald I. Orenstein                           Phone: (905) 820-7886
International Wildlife Coalition              Fax/Modem: (905) 569-0116
1825 Shady Creek Court                 
Mississauga, Ontario, Canada L5L 3W2          mailto:ornstn@inforamp.net