Re: origin of bats/reply 2 to TMK

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

David Marjanovic writes: 

> ----- Original Message -----
> From: "Erik Boehm" <erikboehm07@yahoo.com>
> Sent: Wednesday, June 25, 2008 2:13 AM 
>
> > While the presence of what appear to be wings does not prove they were 
> > used for flight, it is the best explanation.
>
> Well... *Velociraptor* had wings, too, yet it clearly didn't fly.

Perhaps not as an adult. Has anyone ever tested the 'Juvenile Volancy' 
theory for larger dromaeosaurids? 

Sparrows seem to get by on stubby little wings, although if you scaled them 
up non-allometrically they'd be land-lubbers. Perhaps the smaller mass and 
larger relative forelimb size of a very young *Velociraptor* may have enable 
some degree of volancy, which it grew out of as an adult. Certainly many 
modern animals spend more time in the trees as juveniles than as adults 
(Komodo monitors for instance). Just exchange 'trees' for 'trees and/or air' 
in the case of dromaeosaurids. 

Feathered forelimbs would have still been useful in adults, although for 
non-volant activities such as display or brooding. Juveniles however 
generally don't need to perform sexual displays or to protect eggs. Lions 
don't grow manes until they're old enough to need them, and juvenile 
peacocks don't have large tails, since these are expensive structures to 
grow and maintain (too expensive on juveniles anyway, who have no immediate 
need for them). So the presence of fully developed 'wings' on juvenile 
dromaeosaurids like 'Dave' the *Sinornithosaurus* tends to suggest other 
functions are more likely (at least initially). 

___________________________________________________________________ 

Dann Pigdon
GIS / Archaeologist              http://geo_cities.com/dannsdinosaurs
Melbourne, Australia             http://heretichides.soffiles.com
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