T.Rex may have been a big lumbering open country carrion eater that evolved from a smaller, fast jungle predator, similar to a raptor. Evolution works with what it has available, it does not design for optimum configuration from the start. Just think, we started off in the trees, but quickly adapted our hands and feet to the savanna, merely by standing erect. When the forests disappeared we adapted. We are plains dwellers, but all our closest relatives are all tree climbers, and they have left that heritage in our anatomy.

It just now occurred to me, listening carefully to both our arguments, we can certainly bend the facts to fit the kind of evolution we favor to have occurred. Just like in politics, eh?

Roy Chapman Andrews found the bones of an Allosaurus mixed up with those of a duckbill dinosaur. The former had probably been killed and buried by a flash flood while dining on the latter. Indeed, the Allosaur's teeth fit the tooth marks in the duckbill's bones. But that doesn't prove the Allosaur actually brought down the duckbill, just that he was eating it.

The deciding facts will have to come from the bones. If it can be convincingly demonstrated by biomechanical analysis that T.Rex's legs were incapable of moving that body at high speed through heavy undergrowth, then the open country carrion eater hypothesis makes sense. (I actually read a discussion of a biologist who feels he has proven this.) If he is mistaken, the jungle predator concept still holds. But its going to take anatomical observation and calculation to settle that, not reason and "logic" which is what we're doing. Unfortunately, if sufficient evidence is not available in the fossil record, we may never know for sure. I don't think we can figure it out using "common sense".

As for the tiny hands, who knows? I'm inclined to believe they were festooned with colorful feathers used for courtship dances, like coquettish Japanese fans, but no one really knows. BTW, you do know T. Rex was covered with feathers, don't you?

In a related theme, I recently read some paleontologists now believe the Triceratops bony crest was too weak to be used for defense, it was brittle, porous with blood vessels, and would have bled profusely if damaged; they suggested it might have been covered with chromatophores, like a a chamaeleon, for signaling and camouflage.

As for where the big herbivores live...today in Africa, all the big herbivores live in the grasslands, not the rainforests. The big predators follow them, they live in the Serengeti, not the Congo.

I guess the point I'm trying to make is that evolution makes, or fails to make, adaptations in ways that don't always seem logical or reasonable to us. I know, the idea of bad-ass T Rex as a craven vulture (not a fierce and noble predator) doesn't fit in with our preconceptions. But even among modern hunters, dead prey that doesn't fight bank is always preferable to a food source that can injure you. Lions and bald eagles will always go for road kill, if available.