Re: feather origins (was Help Please)

["Waylon Rowley" <hot__male60@hotmail.com>]

My iguana (and a host of other reptiles I have owned) seem to slough their 
skin every 2-3 months. And they don't loose all of it at once, it comes off 
in patches (which seem to irritate them, they scratch at it or eat it when 
they can). BTW, the entire scale doesn't come off, just the outer shell of 
it. Birds like the african grey parrot we have in my house loose their 
entire coat of feathers over the course of about six months. They also come 
off in small patches. As for crocodilians, I'm not sure. The caiman (kinda 
like a mini-croc) I took care of had some sections of its scutes peeling 
around the edges....so maybe the outer surface of their scutes come off in 
smaller flakes. I'm pretty sure the scales on the feet of crocodilians is 
shed. I know that the scutes on the legs of birds are shed, so I think it's 
a fair assumption to say crocs shed theirs too. Something else you might 
find interesting is that birds grow "pin feathers" which are 
purplish-colored spikes that when the correct length are popped open by the 
birds beak and the internal feather is released. This is the reason parrots 
love to have their heads scratched- your loosing the cover of the pin 
feathers they can't reach. As for dinos? I have NO idea. If you ever have 
the misfortune of meeting a Megaraptor (Hey! Jurassic Park is still a 
possibility!), I wouldn't try to scratch its head to get on its good side. 
Speaking of pin feathers....someone should take a look at Sinosauropteryx 
and Sinornithosaurus to see if they can find a few, that would be a good 
indication of a more complex feather morphology than the
so-called "hairs", and they should preserve better. For more info on the 
scute-to-feather transition, go to:
http://www.dinosauria.com/jdp/archie/scutes.htm
Interesting stuff.




_________________________________________________________________
Get your FREE download of MSN Explorer at http://explorer.msn.com