T-rex
(Tyrannosaurus rex)

Although Tyrannosaurus has been surpassed in length as the largest Therapod, it still remains as a creature of enormous size and strength. With the largest teeth of any dinosaur, powerfull jaws and strong back legs to move its 5 tonnes weighing body, it really is the king of the Terrible Lizards.
This ultimate carnivore was just using its one meter long jaws to kill its prey. The little arms where out of scale and useless, it had a long and heavy tail as counterbalance for the massive head.
Despite its size Tyrannosaurus was lightly constructed, with hollow bones and great windows in the skull. Alone or in pairs, Tyrannosaurus probably trailed migrating herds of horned and duckbilled dinosaurs, picking off the weak, young and sick. Other tactics might have involved waiting in ambush then charging, jaws wide open, bringing down its victim with its teeth, after a short chase.