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RE: Duckbill necks
At 07:43 PM 9/2/98 -0700, Stewart, Dwight wrote:
>Hmmm... Out of this, here is the item that peaks my curiosity:
>has ANY evidence ever been found of dinosaur tail dragging?
With one possible exception - absolutely no.
The one (possible) exception is a series of iguanodont (?or hadrosaur)
prints in the top of a coal seam. I have heard that in some of the
sections it appears the animals were feeding on trees or bushes growing in
the swamp, and *may* have dropped their tails while rearing to feed.
Not having been able to achieve access to the journal in which these prints
were published, this is only about third hand, and quite unreliable.
Beyond these, *every* series of dinosaur footprints I know of has no trace
of a tail.
> Partly I ask this
>because we have a pretty good representation of dinosaur tracks
>in Texas & I make a point of seeing all I can. Growing up on a
>ranch, I have seen many different kinds of tracks, EVEN
>alligator slides (yep, we have an occasional Gator in Southern
>Texas! :-)) and tailing dragging, even by a 3.0 meter long
>gator leaves a definite impression.
Quite so. In this case absence of evidence *is* evidence of absence. The
*extreme* rarity of dino tracks with tails marks is quite good evidence
that the tails did *not* drag.
[Indeed I use this criterion as one of my checkpoints for determining the
quality of children's dinosaur books - as there is no excuse for missing
this even in a grade school level book].
> Or, are we talking about
>tail positioning that is more subtly aligned than either
>parallel to the ground or dragging?
Well, details of life position are hard to determine.
However, in *some* dinosaurs the presence of stiffening ligaments in the
tail places considerable restrictions on tail mobility. In these
dinosaurs, at least, a tail that was straight and stiff seems fairly well
established. And I have seen no evidence for any dinosaur having any other
*habitual* position, though one must allow for considerable voluntary
variation in tail position.
> As far as public misconceptions about dinosaurs, I am
>occasionally asked about things like velociraptor being ~ 2.0
>meters tall & I take the time to explain that the velociraptor
>was only one type of Dromaeosauridae, & that is was 0.8 meters
>tall, 1.8 meters long, & MAYBE, MAYBE weighed 100-110 kgs.
>I explain there were "human sized" Dromnaeosaurids, though.
>.. or those awful movies in which they used lizards
>& alligators for dinosaurs! :-)!!!
Heck, they didn't even do a very good job of *disguising* them! I can
usually identify at least the genus of reptile being used.
[Oh, look, another "giant" monitor].
May the peace of God be with you. firstname.lastname@example.org