From reading all these questions and answers,which seem to me that most involve something about a Tyranosaursus and/or Spinosaurus,the Tyranosaurus rex is so different from other therapods it's actually kind of scary.Was there a reason for Tyranosaurs rex to be so different like have a more powerful bite and have his teeth set different from other predators? Or was that the way they just evolved,to be THE ultimate predator?
from J, age 16, Atlanta, Georgia, America; July 27, 2001

TOM: I always thought that T. rex was beautiful rather than scary, but maybe that's just me :-). The differences between Tyrannosaurus and non-tyrannosaur theropods was simply the results of its own particular evolutionary history: evolution works by sorting out among the natural variation that occurs in a particular population. So there wasn't a "reason" as such for T. rex to have wound up with a more powerful bite. That being said, tyrannosaurs lived in an environment where their main potential prey were pretty sophisticated (duckbills and horned dinosaurs), so nature would favor some form of sophisticated predator over more primitive models.