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Re: Deinonychus claw use and origin of flapping

On Fri, Dec 16th, 2011 at 12:02 PM, Tim Williams <tijawi@gmail.com> wrote:

> So the question becomes: Were the changes to the distal limb elements
> (= the putative incipient scansorial/arboreal characters) adequate to
> allow theropods to climb trunks or grasp branches, given the
> constraints imposed by the rest of the body? 

That assumes that arboriality was practiced by any theropods (avian or 
otherwise) before 
advanced flight capabilities were available. Early avians could just as easily 
have been using their 
limited climbing skills to allow them to nest on cliff faces, and not be 
utilising trees at all. There are 
a lot more things in the world to climb than vertical tree trunks.

Living near cliffs would be ideal for a creature that could sort-of fly, and 
for whom terrestrial 
locomotion was still important. They could run from danger on the ground when 
it was a sufficiently 
successful response, and if really pressed could launch themselves off a cliff 
edge in order to 
escape predation. The same may have been true for pursuing prey - chase prey 
about on the 
ground most of the time like their ancestors did, and if they proved too adept 
at avoiding capture 
then attempt to heard them off a cliff. The non-volant prey would most likely 
fall to its death, while 
the sort-of volant predator could glide/parachute down in relative safety to 
dine on the pre-
tenderised carcass.


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