Physical appearance and biologyEdit
Tyrannosaurus was one of the largest theropod dinosaurs ever, reaching lengths of 12-13 meters (39-42ft), weighing 6-7 tonnes, and a height of 4-4.3 meters (13-14ft). It could run up to speeds of 24.85 mph thanks to some of its bones being hollow. Its brain was well developed, which gave it excellent senses including eyes like that of a hawk, great hearing, and advanced olfactories that allowed Tyrannosaurus to efficiently smell prey. 
Tyrannosaurus' skull was 1.5 meters (5ft) long and had a bite force of 3 tons or the weight of an elephant.Its teeth were like thick pegs, being 12 inches long with the root included, that could go through most prey, including their bones. Tyrannosaurus could have also had toxic spit that it used to bring down animals.
Tyrannosaurus eggs are believed to have been the size of a mango and were bird-like. Juvenile T. rex were slender, had long arms, a weaker bite, and were faster, but as it grew older its arms would shorten, its head would grow larger and powerful, it became stockier, and it became slower. T. rex could get as old as 28 years.
Behaviour and traitsEdit
Tyrannosaurus rex was a hypercarnivore. Its prey consisted of ceratopsids (Triceratops), hadrosaurs (Maiasaura and Edmontosaurus), Pachycephalosaurus, and even sauropods like titanosaurs. It has been shown to be a solitary hunter. There were no known predators of Tyrannosaurus excpet its own species. Nature hazerds, such as forest fires, also played a role in stabelizing T. rex populations.
Classification and ancestoryEdit
Tyrannosaurus was related to the smaller and more slender Gorgosaurus that lived millions of years before it as well as other tyrannosaurs, but it was more closely related to the similar looking Tarbosaurus that lived in Asia.
Tyrannosaurus is one of the viewable dinosaurs in the app. Several images depict it attacking Triceratops and Maiasaura.
A Tyrannosaurus rex named Malachite pursues the Pachycephalosaurus Ficus throughout the book before the dinosaur he pursued kills him by pushing him into a nearby lavaflow in the chapter "The Hunt For Food".
Behind the scenesEdit
Unlike what is shown in Walking with Dinosaurs: Inside Their World, Euoplocephalus and Maiasaura were long extinct before Tyrannosaurus rex first evolved.