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Dive! Dive! Dive!
Jeffrey Martz, martz@holly.ColoState.EDU wrote:
> The only particular evidence I recall was that you didn't break
> your own neck when you took a spill on your motorcycle. I assume
> you weigh 200 lbs or less. T.rex weighed about 10,000. There is no
> comparison. If you spike an elephant into the ground at 15 mph, it
> is not going to "skip" over the pavement the way you did when you
> took your high speed spill.
> I have to admit I don't recall what sort reflexive actions you
> propose a five ton animal could use to keep from damaging itself
> when it falls. Shoulder rolls? That would be something to see.
> I was not aware that any running theropod trackways large
> enough to have come from tyrannosaurids or a similar sized theropod
> had been found. Which trackway clues are you referring to?
> You are making the assumption that T.rex could not have
> survived, as either a predator or scavenger, without being able to
> run more than about 20 mph. Why is that? How much faster are you
> assuming its main prey animals could run, and why?
> Dr. Farlow's calculations are based on the laws of physics,
> which is about as real as you can get.
As horriffic as it is there are films of African elephnts being "spiked"
into the dirt while at full charge, as the result of big bore rifle
impacts. While the elephant doesn't skip like a stone it does not slam into
the ground and stick like a Tiger Woods approach shot. Inertia happens, and
just watch the train try to "spike" itself in "The Fugitive". Skidding,
unless friction was greater during the Cretaceous, happened. The very vast
difference in body style makes such comparison almost useless any way.
Tyrannosaurus rex was much more streamlined than any extant large land
Trackway evidence was presented on the Paleoworld episode Dr. Lockley
appeared on of a large predatory dinosaur "disturbing" a herd of smaller
dinosaurs, suggesting a chase. Notice I said suggesting a chase in my
origional posting. I don't know where this trackway is, write Paleoworld if
The Denver MHN Hadrosaur with a Tyrannosaurid bite in its tail is evidence
of predation on a species capable of sustained herd speed travel and very
likely much faster when threatened. Trackway evidence for the Hadrosaurians
is pretty well documented if I'm not mistaken. Tyrannosaurus rex would
almost certianly have to run in order to leave us the evidence pressent in
the Denver specimen. If the prey species was not attacked from a stealthy
position then running would have been the ONLY other option for a fresh
kill meal. If the Hadrosaur specimen was attacked from such a stealthy
position he was extremely lucky to have escaped to heal. Healed bites are
evidence of predation, not scavaging.
The Black Hills Institute has a copy of the Tyrannosaurus rex that is the
subject of the "falling down might be fatal" paper (sorry Dr. Farlow), and
is posed at the moment of truth at the tail of a half grown Hardosaur,
Edmontosaurus(SP?). The head of the Tyrannosaurus rex is less than eight
feet from the ground, and his back is no more than a couple feet higher. If
the Tyrannosaurus rex fell from this postion, and not the rearing to 20'
suggested a Tyrannosaurus rex would fall from, the physics numbers change
radically. The "assumption" I make is that Tyrannosaurus rex ran with its
head low to the ground, after having seen skeletal displays. Balance for
the Tyrannosaurus rex seems right in this pose. Since the "predation"
elephants and other huge herbivorous mamals act on is made against
stationary targets any motor control comparison there is useless.
Unaddressed in the paper is unknown neck strength, reaction time, skull
flex, and a other attributes of Tyrannosaurus rex we just don't know yet.
Dr. Falrow's calculations, as detailed as they are, cannot model the
aspects I cite.
I agreed with the "idea" that Tyrannosaurus rex could kill itself as the
result of a fall, but placed the likelyhood of such very low. As I've
repeatedly mentioned there is not fossil evidence to firm up either side of
this coin. Just about anything that has ever lived can make some sort of
error in judgement leading to death, but how often does it happen aside
from humans? Even earthworms have self preservation behaviors hardwired.
The reason I dispacted such a strongly worded posting prior to this was not
so much the material but the tone of the reference to my stand on this
matter. Suggesting my line of thinking is out of touch with reality
deserves it, considering the existing physical evidence. Igonore what you
want, if it makes your beer fizz, but don't expect me to be a whipping boy.
(Yes, Betty, I thank you for the reminder.)
(with arms wide,, eh Mickey?)
[ And sails unfurled, hopefully. -- MR ]
Trying not to go ballistic,