As a famous dinosaur that it is, Tyrannosaurus rex has been depicted dozens of times in novels, comics, and movies. sometimes more successful than others. But, without a doubt, the incarnation of this dinosaur that has gone down in history has been that of the movie Jurassic Park and its sequels. Unfortunately, this fame has meant that film licenses have passed into popular knowledge as if it were scientific data. Today, we are going to separate fiction from reality.
Tyrannosaurus rex is part of the group of theropod dinosaurs, to which all carnivorous dinosaurs, including birds, belong. In fact, next to other large carnivorous dinosaurs, such as Spinosaurus or Carnotaurus, Tyrannosaurus is more closely related to birds. It lived about 68-66 million years ago, at the end of the Cretaceous, in North America, living with other dinosaurs such as Triceratops, Ankylosaurus, Pachycephalosaurus or Alamosaurus.
It is a dinosaur that gives its name to a whole family, the tyrannosaurids , to which Gorgosaurus, Tarbosaurus or Albertosaurus also belong. Like other tyrannosaurids, and in stark contrast to other groups of theropod dinosaurs, Tyrannosaurus had very short arms with only 2 fingers. Despite this small size, the bones of his arms show highly developed muscle attachments , a sign that he would have great strength.
In contrast to such small arms, its jaws compensated: Tyrannosaurus rex has a huge skull armed with very robust teeth . Unlike the teeth of most theropods, which are knife-like, sharp and flattened, the teeth of tyrannosaurids are very thick . Biomechanical studies have been carried out, and it has been seen that these jaws, armed with such teeth, were capable of exerting a bite force of a minimum of 4 tons, capable of crushing bones and tearing meat from their prey in one bite. The bones of the skull and the vertebrae and ribs of its neck show very strong muscular attachments, larger than those of other theropod dinosaurs. In such a way that it would have been able to tear off large chunks of its prey with each bite.
Its hind legs show a good adaptation to running . However, biomechanical studies have been carried out in which it is proposed that the leg bones of an adult tyrannosaurus, weighing between 7 and 9 tons, would suffer a lot when running. Possibly their rapid displacement would be walking as fast as possible, without being suspended in the air, and they could not exceed 18 km/hour. However, these adaptations in their foot bones and the leg anatomy of younger tyrannosaurs suggest that they may have been good runners in their youth.
The first specimen was described by the North American paleontologist Henry Fairfield Osborn in 1905. Since then we have known more than 30 specimens, some more complete than others, and thanks to this we can know the variability of this species, which could reach 13 meters in length. length , the 9 tons of weight, and of which we have many studies of its paleobiology.
Thanks to its popularization, and its constant presence in the Jurassic saga movies, many of the characteristics of this dinosaur in the movies have become popular knowledge. Sometimes with more success than others. For example, in Jurassic Park there are constant references to his vision being based on movement: it is mentioned both in the middle of the excavation, when talking about the raptors, and later when Rexy escapes from her enclosure. And in the sequels this idea is maintained again and again.
This idea is born in the novels of Michael Crichton, where he talks about theories that are in force in that world. In these novels, paleontologist John Roxton studied internal casts of the cranial cavity of Tyrannosaurus and concluded that they bore a close resemblance to the brains of some amphibians, and therefore concluded that Tyrannosaurus ‘ vision was adapted to movement. This theory, launched within the universe of the novels , reaches us in the movies, where mention is made of it constantly. And that’s the only reason the movement-adapted vision of tyrannosaurus is talked about, it’s not based on real-world scientific theories, based on data from actual fossils. In fact, in the novels the protagonists are able to contrast this hypothesis in the countryside, or rather, on the islands, and conclude that it is false. But this testing of theory in the novels is not seen in the movies.
Regarding their appearance, tyrannosaurs are shown in movies as completely scaly . There are impressions of the fossil skin of Tyrannosaurus rex, in which scales are indeed observed. But all this debate comes down to their ancestry: tyrannosaurids are more or less related to birds, and their relatives have primitive, filament-like feathers. Hence, let’s say that by family it would have to be feathered and that is why you will see reconstructions with some loose feathers, which at first glance may look more like hair than fully developed feathers, as we saw in the Prologue of Jurassic World Dominion. In fact, we have already dedicated an entire article to this topic.
In general, the peculiarities of the tyrannosaurs of the Jurassic saga can be explained within fiction: the dinosaurs that they have been cloning for years do not have pure DNA and, if they did, their appearance would be very different…
References:
Hutchinson, J.R.; Garcia, M. 2002. Tyrannosaurus was not a fast runner. Nature, 28; 415(6875):1018-21.
Xu, X. et al. 2004. Basal tyrannosauroids from China and evidence for protofeathers in tyrannosauroids. Nature 431 (7009): 680-684.
Bell, P. R. et al. 2017. Tyrannosauroid integument reveals conflicting patterns of gigantism and feather evolution. Biology Letters. 13 (6): 20170092.
