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RE: spinning stegos



I'd be a little surprised if Stegosaur ever had to rotate more than a few
degrees to bring it's tail in range of an attacker. 
Reasons?
>From what we can observe from modern predators (not a certain analogy - but
the best we've got) there are two favoured attack positions.
The first comes in from the side on either of the front quarters and
attempts to tear the throat of the victim. Stegosaurs had lots of plates on
the back of a comparatively skinny neck - probably wouldn't appeal to a
predator.
The second favoured attack method involves chasing from behind and tearing
lumps out of the hind quarters of the prey, using weight to bring it down,
or "hamstringing" it. This method is popular against creatures who run away
from the predator, with a speed approaching that of the predator. In this
scenario, a swinging spiked tail, covering the rear quarters, should be an
effective deterrent.
The stegosaur doesn't have to do any crazy gymnastics to bring its foremost
weapon to bear - it just does what is natural - runs away.

-----Original Message-----
From: Jaime A. Headden [mailto:qilongia@yahoo.com]
Sent: 24 July 1998 07:16
To: dinosaur@usc.edu
Cc: jdaniel@aristotle.net
Subject: Re: spinning stegos


Joe Daniel wrote:

<I have heard, read some stuff about how stegosaurs defended
themselves. They were thought to be rather slow and that the plates on
the backs were not particularly useful as armor per se.>

  Not as armor as in ankylosaurians, or even titanosaurs, but what do
you think the pointy tips were for? :)

<That leaves the tail spikes.  Being conservative the tail can protect
only 1/4 of the body. Now, stegosaurs support roughly 75% on their
hind legs.  So I thought that it would be a simple matter for them to
briefly rear up and take a side step allowing them to spin very
quickly.  I am not suggesting they spun like a top during combat, but
considering their center of balance, surely they could spin faster
than a predator could circle around them. This would not work so well
for pack hunters as the stegos would not be able to spin around fast
enough to keep several small agile hunters away.>

  Have you seen the recent episode of _Paleoworld_ where animation was
shown, originally produced for the second or third episode of the
remarkable _Dinosaur!_ series ("Tale of a Bone", I think it was); that
animation featured a stegosaur, a ceratosaur, and a nasty scenario
that no doubt would have occured. The stegosaur shocked me by wagging
its plates, but it most certainly seems to have spun about on the hind
leg (one at a time) to fling the tail in the direction of that leg
(and the targeted theropod).

  Now, as for whether it was possible, the legs, the short back the
high neural spines of the back and tail . . . yes.

==
Jaime A. Headden

Qilong, the website, at:
http://members.tripod.com/~Qilong/qilong.html
---
All comments and criticisms are welcome!

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