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Diplodocid duck-and-cover



If anyone's interested (a big "if"), I've roughed out a quick sketch of
Diplodocus in tail-lash mode, looking at the world as us Australian's do
(from down under, that is).
http://dannsdinosaurs.terrashare.com/diplodoc.gif

This posture is starting to make more sense all the time. If the spikes
along the neck continued down to the head, this might provide some
protection while the head is tucked under. The neck itself is mostly in
the neutral position as predicted by the Dinomorph project, with most of
the flexure being at the skull joint itself rather than in the neck
vertebrae. With the neck straight out and closer to the ground, it would
make an excellant counter-balance for the flailing tail.

In effect the animal has reversed itself. With many dinosaurs
(especially theropods) the tail is simply a rather undynamic counter
balance for the business end of the body (usually the neck and head). If
Diplodocids adopted this defensive pose, then the neck would be acting
as counter weight, and the "business end" would be the lashing tail.

Is there any physical reason why this posture would not be feasible?
Does the joint between the head and the neck allow for such a degree of
bending? Would the sauropod's legs be too close together to be able to
see between them? I'm trying to find reasons why this posture wasn't
likely, but I'm having a hard time doing so. I found a picture of a
Diplodocus skull from front-on, and assuming it hadn't been heavily
reconstructed and there wasn't any post-mortum distortion, it appears to
have a degree of stereoscopic vision, just right for judging distances.
More so than a horse or cow, it seemed to me.

Try the same experiment I conducted. Make sure you're alone (this is
important, as you'll see). Get down on your hands and knees and pretend
you're a sauropod with a huge tail. Imagine turning your back on an
agressor (lets say a adolescent Allosaur with not enough sense to leave
an adult sauropod alone). If you turn your neck to one side to see
backwards, you'll notice your other flank is exposed and in a huge blind
spot. Now try bending your neck down to look back between your legs. Not
only can you see your imaginary tail, but you've got pretty good
peripheral vision of both flanks as well. If you need to straighten your
neck from time to time in order to check what's ahead of you, it takes
much less time than bending a huge neck from one side to the other
would. Now imagine sweeping your tail low and swiping the Allosaur's
legs out from under it with pin-point precision. Fun, isn't it? Much
more satisfying than a randomly lashing tail.

-- 
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Dann Pigdon                   Australian Dinosaurs:
GIS Archaeologist           http://dannsdinosaurs.terrashare.com
Melbourne, Australia        http://home.alphalink.com.au/~dannj/
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