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

[Dann Pigdon <dannj@alphalink.com.au>]

On Mon, Jul 5th, 2010 at 2:09 PM, Jura <pristichampsus@yahoo.com> wrote:

> --- On Sun, 7/4/10, David Marjanovic <david.marjanovic@gmx.at> wrote:
> > >  During the last Friends of
> > Dinosaur Dreaming meeting late last year
> > >  it was hinted that Leaellynasaura may have had a
> > hyper- long tail
> > >  (the full-scale drawing held up - with the help
> > of several people -
> > >  had to be seen to be believed!).
> > 
> > This was confirmed at the SVP meeting last year. The length
> > is utterly mind-boggling.
> 
> ++++++++++++++++++++++++++++++++++++++
> 
> Neat. I wonder if the tail was used to lure predators away, and/or establish 
> a dominance
> hierarchy as in many lizard species. 

Just imagine if Leaellynasaura had a bushy fox-like tail covered in 
protofeathers. Not only would it 
make a handy scarf for wrapping around the body while sleeping (as with arctic 
foxes), but by 
raising their tail-hackles and swishing that impressive tail about they could 
make themselves look 
several times larger than they actually were. If the bluff failed and they were 
forced to flee, then a 
predator might get nothing but a mouthful of tail fuzz for its trouble.

Matthew Herne's SVP abstract says:

"Dorsoventral and cranial expansion of postzygapophyses (up to 44% of vertebral 
body
length) on vertebrae in the terminal half of the tail of L. amicagraphica 
suggests an
alternative to ossified tendons to provide caudal axial rigidity."

In the absence of ossified tendons, would such a postzygapophysis arrangement 
allow for flexibility 
in the horizontal plane, while stiffening the tail sufficiently in the vertical 
plane to keep it off the 
ground? If not then the arctic-fox-tail analogy falls flat, since it would take 
significant flexibility in 
the horizontal plane to wrap the tail about the body.

-- 
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Dann Pigdon
Spatial Data Analyst               Australian Dinosaurs
Melbourne, Australia               http://home.alphalink.com.au/~dannj
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