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Re: Feathers-for flight or insulation?



At 12:44 PM 02/02/1998 -0700, you wrote:
>Chatters-
>
>A question for your collective input...  I will be presenting a program on
bird
>adaptations as part of our local Audubon chapter's Introduction to Birding
series for
>beginning birdwatchers.  A birding friend of mine suggested I touch on the
subject of
>why birds even evolved feathers in the first place.  Did feathers evolve
for flight
>purposes, perhaps to make it easier for the 'ancestral bird' to pursue
prey items, or did
>feathers evolve as a means of insulation against the elements?  

The short answer to this is that nobody knows, but lots of people have
opinions!  The question is tied up in the whole issue of bird origins, and
a number of recent books have treated this.  To my mind the best one
(because it is not a polemic for one point of view or the other) is "Taking
Wing" by Pat Shipman.  The book has quite a bit on the various theories
about feather origins - too long to quote here.  One of the big questions
is the nature of the epidermal structures on the recently-discovered
Chinese dinosaur Sinosauropteryx prima.  If they are indeed a sort of
"proto-feather" (as some have suggested and others, notably Dr Alan
Feduccia who vehemently opposes a dinosaurian origin for birds, have hotly
denied) then it would seem that the insulation theory is more likely - but
you have stumbled into a hot, ongoing debate that has fired up recently
with the new discoveries of early birds and birdlike dinosaurs in China and
elsewhere, and you will not come up with a definitive answer based on
current evidence.
--
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