Head study of a feathered tyrannosaurus. T rex was an apex predator of the Late Cretaceous period, living in the last 2 million years of that time (68-66 million years ago). It had the strongest bite of any known dinosaur, enough to puncture bone. Its arms, though small, were well muscled and it may have used them to grasp prey during a kill. Its main method of attack was an ambush. It would run at the prey with its mouth agape and inflict a crushing bite. Estimates for its speed vary widely but it's unlikely it could run much faster than 10-25 mph because it would require far bigger leg muscles than it possessed. It probably fed on triceratops, edmontosaurus and similar animals. There is no firm proof that it had feathers, but dinosaurs closely related to it, from which is descended, definitely did have primitive feathery integuments, so it's plausible that T rex had them too.