Artwork of a pair of tyrannosauruses, male (left) and female. Tyrannosaurus rex was an apex predator of the Late Cretaceous period (68-66 million years ago). 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. In this image, the male is depicted with a feathered mane and osteoderms (body deposits on its back and tail), both of which the females lacks. The male is also more heavily built than the female.