Tyrannosaurus Rex and Velociraptors: The History of the Cretaceous Period’s Most Famous Carnivores

Beginning in the Triassic but especially in the Jurassic period, reptiles came to dominate the oceans, the land and even the skies. There has never been anything else quite like this period in terms of the success of a particular type of creature. For almost 200 million years, reptiles were the only significant creatures on Earth. They were so successful and so diverse that they evolved to take advantage of every available habitat and no other type of large creature had a chance to develop.

The massively popular 1990 novel Jurassic Park by Michael Crichton and its subsequent movie adaptations led to a huge resurgence in interest in dinosaurs and the prehistoric world. That interest continues to the present day, even though most of the dinosaurs in Jurassic Park weren’t actually from the Jurassic period. Triceratops, Velociraptor, TyrannosaurusRex and the huge sauropods such as Brachiosaurus that feature in the book and movies all actually belong to the Late Cretaceous period, more than 40 million years after the end of the Jurassic. Regardless, certain kinds of dinosaurs remain instantly recognizable, and among them, the “king” is undoubtedly the Tyrannosaurus.

The first discovery of a Tyrannosaurus was made in 1902 and the largest carnivorous dinosaur ever found at the time quickly gripped the popular imagination. Even its name was dramatic - Tyrannosaurus Rex means “King of the Tyrant Lizards.” The T-Rex as it quickly became known didn’t appear until the last age of the Late Cretaceous period, the Maastrichtian, but when it did, it was the biggest and most terrifying of all the theropod predators. The T-Rex was around 13 feet tall at the hips (its tallest point since it isn’t believe to have stood upright), it was over 35 feet long, and it weighed about nine metric tons. Like most therapods, it had very powerful hind legs and much smaller fore legs, so the front legs look almost comically small. This dinosaur also had a large and powerful tail to counterbalance its very large head (some T-Rex skulls are nearly five feet long). Within the skull was a massive jaw lined with teeth up to a foot long. A reconstructive study has estimated that a T-Rex jaw was capable of exerting a pressure of over 55,000 Newtons; the equivalent of almost six tons of pressure. It was fast too, with the same study estimating that a full-grown T-Rex would have been capable of moving at speeds of up to 25 miles per hour.

Though it is often depicted as the apex predator, the T-Rex was mostly a scavenger that ate the carcasses of dead dinosaurs, but it was indeed a hunter, using its speed to prey on plant-eating dinosaurs such as Edmontosaurus and Triceratops.

Thanks to the movie, there has been some unwitting confusion over the identity of the Velociraptor, and this confusion was due in large part to the fact the name sounds far more scary than the creature to which the name originally belonged. Moreover, the creature to which the label was applied in the novel and movie was actually a distant cousin named Deinonychus, but as the story goes, the author, Michael Crichton, thought “Velociraptor” sounded “more dramatic.” The actual Velociraptor lived not in the badlands of North America, but in the badlands of central-eastern Asia, and it was not nearly as intimidating as Deinonychus. In fact, the main species of genus Velociraptor - Velociraptor mongoliensis - was no bigger than a turkey. Thus, in a very real sense, the Velociraptor has taken on a larger-than-life reputation.