RE: T. rex Predation

[MarkSabercat@aol.com]

Tim Donovan (<uwrk@yahoo.com>) wrote:

<The allosaur technique of of running into the prey with jaws agape i.e. 
relying on legs as a substitute for strong jaw musculature, would have been 
far less effective when the prey fled--it diminished the theropod's speed 
relative to the prey and hence the impact and penetrating effect of an attack>

I think the whole idea of large theropods literally crashing into their prey 
with jaws agape is unlikely: effective tooth penetration would probably 
require an angle of 5 degrees or less from the perpendicular, otherwise 
significant tooth breakage would occur. This is why, by homology, the 
"stabbing" hypothosis for sabertoothed cat predation has been discarded in 
favor of the "shear bite" idea. Allosaurids also had shorter limbs, which 
meant they would be slower than tyrannosaurids or abelisaurids in pursuing 
some prey, unless sauropods were the prey.

<(Pachycephalosaurs were too small for adult T. rex.)>

I doubt this. Predators, both terrestrial and aquatic, are usually highly 
opportunistic when it comes to prey selection, and I can't see a long-legged, 
40 mph + adult tyrannosaurid turning down anything it had a reasonable chance 
of catching; tigers, after all, will go after grasshoppers when they can't 
find anything else to eat.

As a corollary, the relatively long limb proportions of of tyrannosaurids vis 
a vis allosaurids, the arctometatarsalian condition of the foot and the huge, 
long teeth are among the best anatomical counters to the "T. rex as an 
exclusive scavenger" argument, as well as the ecological ones.

--Mark Hallett