T. rex: Size and Behavior Before we imagine T. rex in today’s world, let’s take a look at how T. rex lived. T. rex was a fearsome predator, reaching 12 feet high and 40 feet long.

Tyrannosaurus rex may have been a cannibal. A young Yale University scientist, Nicholas Longrich, reports finding tooth marks on the feet and arms of four different T. rex fossils -- marks that ...