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Re: Bird vs. theropod dinosaur tracks/trackways



-----Original Message-----
From: Darren Tanke <dtanke@dns.magtech.ab.ca>
To: dinosaur@usc.edu <dinosaur@usc.edu>
Date: 12. april 1999 3:52
Subject: Bird vs. theropod dinosaur tracks/trackways


For theropods? Trackways are in a nice straight line and the
>toes pointed more or less forward.
>

Some theropod trackways show that toes were pointed slightly inward.
Cretaceous theropod trackways in Croatia show that they waddled a bit.
...snipped...
>

> 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?

I presume the birds generally have broader bodies than many theropods -
for which reason their legs are more spread apart - causing them to waddle
a bit more. Also the toes of most of the birds are more slender and
flexible - so pointing more inward to bear the weight of the body better and
keep the balance.

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.

I think there are variations of "wide" and "narrow" walkers in both groups.
Also if the animal is running the trackway tends to be placed closer to the
midline.


Well, I am sure somebody with exact statistical data will confirm (or
reject) my thoughts.


Berislav Krzic (Kr?ic)
illustrissimus@usa.net
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