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RE: Bird reduce their "heating bills" in cold climates



--- On Mon, 7/5/10, GUY LEAHY <xrciseguy@q.com> wrote:

> From: GUY LEAHY <xrciseguy@q.com>
> Subject: RE: Bird reduce their "heating bills" in cold climates
> To: "Tim Williams" <tijawi@yahoo.com>, "Dinosaur Mailing List" 
> <dinosaur@usc.edu>
> Date: Monday, July 5, 2010, 11:21 PM
> 
> Furthermore, scales and feathers can co-occur on the same
> body parts: 
> http://elibrary.unm.edu/sora/Condor/files/issues/v032n01/p0064-p0065.pdf

++++++++++++++++++++++

The examples cited always show malformed feathers, and, or scales, suggesting a 
biochemical miscommunication more than a reversal.

_________________________

  
> It's entirely possible polar dinosaurs grew a coat of
> dinofuzz/feathers over the scales to keep warm during the
> dark winters, and seasonally shed this insulation when
> summer approached.

++++++++++++++++++++++++++++++++++++++

Possible? Yes. Probable? No. As I wrote earlier, it would involve dinosaurs 
exhibiting a trait that we would have no example of today.  

____________________________________________

> Most birds have scales on the metatarsi, but willow
> ptarmigans have a coat of feathers which covers the scales,
> and this feather coat is seasonally shed from the ventral
> portion of the feet:  
> http://elibrary.unm.edu/sora/Condor/files/issues/v079n03/p0380-p0382.pdf

+++++++++++++++++++++++++++++++++++++++++++++++

What the picture in that pdf doesn't show is that ptarmigans don't actually 
have foot scales.

See: 
http://www.nawwal.org/~mrgoff/photojournal/2006/sum/pictures/07-10p36feet.jpg

So growing winter snowshoes, and then dumping them in the summer is perfectly 
reasonable.


> Some theropods also had feathered metatarsi:
> http://www.nature.com/nature/journal/v461/n7264/full/nature08322.html
> 

++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++

Indeed, so many that they probably represent the plesiomorphic condition.

Jason