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RE: Rough & tumble world (was Re: "Dinos of a Feather" )
From: Thomas R. Holtz, Jr. [SMTP:firstname.lastname@example.org]
Sent: Tuesday, March 02, 1999 8:00 AM
To: Patrick Norton
Subject: Rough & tumble world (was Re: "Dinos of a Feather" )
At 07:59 PM 3/1/99 -0500, you wrote:
>Dr. Tom wrote:
>>Grappling with the jaws, sure; tearing and yanking with the
>sure; but rolling around with a 4 tonne _Edmontosaurus_ or 6 tonne
>_Triceratops_ or whatever is a good route for getting your rib
Rough and tumble, yes; lots of damage, yes. But we were talking
about rolling over on its back during routine predation. Rolling
while wrestling a big hadrosaur or _Triceratops_ wouldn't merely
broken bones: this would very likely result in *crushed* bones
(notice how I
used that particular word in the quote above), and ribcages (and
internal organs), etc. Heck, I would expect this is the one time
WOULD get a hepatic piston in a tyrannosaur, as liver gets squashed
into the lungs...
Unlike stop-motion animation movies, you can't just scale up the
small animals and say that large animals did exactly the same thing.
allowances have to be made to the laws of physics and the mechanical
strengths of flesh and bone.
So, sure: body blows, tail slams, kicks and so forth (although even
nelson would be outside of a tyrannosaur's or opponent's ability...)
expected, and a significant amount of breakage did occur. However,
that a _Tyrannosaurus_ vs. _Anatotitan_ predation event was just a
version of mongoose vs. cobra seems very unlikley.
And that's where this thread began: with the question about what
happen to alledged _T. rex_ feathers when it rolled on its back to
with its prey.
(And, come to think of it, rolling on its back would probably be the
possible move a tyrannosaur could do: it loses its height advantage
from above) and its speed advantage, and puts itself in a position
(literally!) where the potential prey item could use its entire
Thomas R. Holtz, Jr.
Vertebrate Paleontologist Webpage: http://www.geol.umd.edu
Dept. of Geology Email:email@example.com
University of Maryland Phone:301-405-4084
College Park, MD 20742 Fax: 301-314-9661
Tom is right on about the physics involved here. Even "logic"
must bow to basic
physics, as somebody or other once said. :-) Bone can only be just
so strong & there
can only be just so much muscle protecting it. The big problem with
a really massive
animal rolling over you (even if you are a 6.5 ton Tyrannosaurus
rex) is F = ma.
And, that's just the ballistic component. Stress induced by
sustained force would
raise the internal pressure on bones & internal organs dramatically.
Also, I would think a Tyrannosaurus rex would try vigorously to
avoid being off
of its feet. Dr. Holtz & others would have a better take on this
than I, BUT - how easy
would it be for a T. rex to REGAIN it's feet from a prone position?
a fight? T. rex doesn't look like it was built to quickly vault to
a standing position,
unless he could get those powerful legs under him.
Also, the point about the height advantage is worth considering
too. Why give that up?
With the exception of sauropods, T. rex was taller than almost all
potential prey animals.
I don't doubt that a Triceratops COULD knock a Tyrannosaur off
its feet under certain
circumstances. I just feel that such an event might shift the
advantage more in the