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Bird vs. theropod dinosaur tracks/trackways

Darren Tanke wrote:

>  1). Why do birds "waddle" (and thus turn their toes inwards) and theropods
> apparently did not (as manifested by the trackway evidence)? Someone thought
> theropods did "waddle", but due to their greater height the direct effect of
> this was somehow "lost" by the time the foot touched the ground (whatever
> that meant!).
>  2). What skeletal or other morphological feature(s) cause a bird to walk
> pigeon-toed and theropods not?
>  3). Could the difference be related to behavior? A suggestion was that
> "waddling" bird tracks were of feeding birds while those of theropods were
> simply walking from point A to B.
>  4). Theropods are able to put one foot directly in front of the other,
> birds apparently not. True? If so why? I'm not a bird footprint expert, but
> if memory serves, I think I have seen some rather straight trackways with
> the middle toe pointing more or less forward.
        Hey, Darren, how large was the sample that this person worked 
with?  I have seen theropod trackways that "waddle" in the Early Mesozoic 
on the east coast.  Hithcock's opinions aside, I think most of us feel 
that those tracks are not "birds."


Josh Smith
University of Pennsylvania
Department of Earth and Environmental Science
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