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Tyrannosaurs hunting sauropods (was late night thoughts: misunderstand what?)
I've just thought of several reasons why tyrannosaurs may have been
ill-designed to hunt sauropods:
Tyrannosaurs had blunter, less blade-like teeth than some other
mega-theropods (carcharodontosaurids, allosaurids, etc) and seemed to have
relied on a powerful crushing bite rather than a messier blood-letting one.
This would seem to restrict them to attacking the neck or tail of a
sauropod, since nothing else would be thin enough to get their jaws around.
Blade-toothed mega-theropods like Giganotosaurus tended to have larger
forelimbs (with more digits) that tyrannosaurs, perhaps indicating they
could have used a 'bite and pull back' strategy to cause huge bleeding
wounds with the upper jaws alone, while raking with the forelimbs. They
could have employed a quick attack on just about any body part, followed by
an even quicker retreat, then waited for bloodloss to do it's job. That's
the same strategy that Great White sharks use on seals.
I suspect that the base of really big sauropod necks (or tails) may have
been too wide for a tyrannosaur to make an effective bite. If the jaws are
too wide when coming into contact with flesh (and probably thick hide), then
they have less leverage with which to be closed. I call this the "giant
peach" hypothesis (after the book "James and the Giant Peach" - when James
is worried about sharks biting the peach while it floated in the ocean,
until an intelligent worm explains why there's really nothing to worry
about). This may have restricted their attacks to either the end of the tail
(which would have been pointless) or close to the head (which is the bit
that can see you coming).
One really big problem with biting down hard on a neck (or tail for that
matter) would have been the presence of a dorsal frill of spikes. They've
only really been identified in one type of diplodocid, but if such
keratinous (ie. non-bony, hence less likely to be preserved) spikes were
common amongst sauropods in general, then they would have been a serious
deterant to biting down hard.
If you're going to tackle something with the mass of a sauropod, then a low
centre of gravity would probably be an advantage. Stumpy-legged
mega-theropods like allosaurids and carcharodontosaurids may have been
better able to withstand a massive shove without fatally toppling than the
top-heavy, long-legged tyrannosaurs.
Tyrannosaur bite marks have been confirmed on hadrosaur and ceratopian
bones, however as far as I'm aware no confirmed bite marks have been found
on sauropod neck vertebrae. The messy slashing techniques of blade-toothed
mega-theropods wouldn't have left any neat puncture marks on bone (in fact
with blade-like teeth you'd go to great lengths *not* to make contact with
bone). I think it's notable that all of the confirmed tyrannosaur bite marks
on herivorous dinosaurs have been towards the back end of the prey. In fact,
as far as I'm aware the only bite marks of any mega-theropods found on the
heads of animals were on others of the same species (ie. intra-specific
Any comments on the above points are welcome - especially if they complete
blow them out of the water (I live to learn).
GIS / Archaeologist http://www.geocities.com/dannsdinosaurs
Melbourne, Australia http://heretichides.soffiles.com