rex and lacked the bone-crushing jaws that T. In fact, its size exceeded Tyrannosaurus, but it was not as large as Spinosaurus. Giganotosaurus was one of the largest dinosaurs ever being 6 meters (20 ft) high, 13.1 meters (43 ft) long, weighing about 6.5-13.3 tons, and larger skull than Tyrannosaurus. 2 In Walking with Dinosaurs: Inside Their World.