During Jurassic June, we had an idea to go above and beyond the articles we would normally bring you - we wanted to get YOU involved. So, after some careful consideration, we decided to dive into the world of the Science behind the Jurassic Park films. What kind of questions did we all have? And who could answer them?
All images in the article ahead are also courtesy of our friends at Jurassic Vault – so go show them some love if you haven’t already!
Let’s delve deep into the world of palaeontology, and how it links to our beloved franchise.
A chicken is really a relative much closer to a T. rex than other bird species? That includes the way it walks.
A chicken is not any more closely related to a T. rex than other bird species. However, fowls like chickens are one of the older lineages of birds and so – along with other relatively ancient groups likes ostriches, emus and tinamous – can be particularly useful in helping us to understand what dinosaurs were like.
However, when it comes to figuring out how dinosaurs like T. rex walked, there is a big difference between them and living birds – the tail. In most dinosaurs, such as Tyrannosaurus, the tail anchored powerful leg muscles, whereas in birds the tail has shrunk, these muscles have moved, and they have developed a unique crouched posture (we can see this evolutionary transition through groups closer to birds, like raptors). This means that Tyrannosaurus would have walked in a rather different way than living birds.
In terms of sizes (and how they moved), which dinosaur is the most and least plausible to its real-life counterpart?
The most accurate dinosaurs in appearance, size and movement are the ornithopods (Iguanodon and the hadrosaurs). We have extensive remains of many ornithopods – especially the hadrosaurs, from which we not only have many skeletons but also extensive skin impressions informing us about their original shape and the texture of their scales. In Edmontosaurus this extends right down to remains showing us the original presence of a soft-tissue crest, as seen in Jurassic World Evolution. Fossil trackways show us that they usually walked on all fours but would have been able to run on their hind-legs, as in-game. They also show that they lived in groups, so their behaviour is also generally plausible – although, in real life, the hadrosaurs would have been more than capable of using their size and strength to fight off smaller aggressors, just as the Iguanodon can.
In terms of size, appearance and behaviour, Dilophosaurus is probably the least accurate dinosaur in the entire franchise. Dilophosaurus was twice as big in real life, at over 6m long. Its head looked very different in real life – the skull was more elongate, with a narrow, hooked, snout. It also lacked an extendable neck frill and did not have venomous spit. The least accurate dinosaur in terms of how it moves may instead Spinosaurus. Some recent studies have suggested that Spinosaurus may have been quadrupedal, very unlike its appearances in Jurassic Park III and Jurassic World: Evolution. However, this remains controversial, as it is difficult to verify from the scant fossil remains we have of Spinosaurus.
Other competitors for the least accurate dinosaur in the Jurassic Park franchise are Velociraptor and Troodon. Velociraptor was much smaller in real life, measuring only 2m long and weighing as much as a turkey. Its running speed is also inaccurate – in real life Velociraptor would still have been able to outrun a human, but would have been nowhere near as fast as a cheetah, unlike in Jurassic Park. In addition, it would not have been able to pronate its wrists in real life. This is a common problem in the depiction of theropods in Jurassic Park, but is particularly noticeable in Velociraptor as it means that, in real life, its hands would probably not have been flexible enough to open doors.
Furthermore, although smart for a dinosaur, Velociraptor would have been about as intelligent as a bird of prey – not as intelligent as an ape, as suggested in Jurassic Park III. This means that their behaviour may not have been as complex as portrayed in the Jurassic Park franchise – in particular, there is no strong evidence of pack hunting between raptors in the fossil record. Velociraptor, of course, would also have had a full plumage of feathers in real life.
Troodon would have had a full pelt of feathers and lacked venom in real life, like the above examples. We also have no evidence of it living or hunting in large mobs. The problems only start there, however. Its… um… unique lifecycle as seen in Jurassic Park: The Game would never happen in real life. A reptile that laid its eggs in bodies would open itself up to problems of infection and disease in the unborn chicks.
Feathers on dinosaurs, we know that some species did have feathers, but I hear that there is no evidence of larger theropods like T. rex having them. So, are feathers, species specific or do we know think most theropod like dinos had them?
Understanding what many dinosaurs looked like is difficult, as skin and feathers are rarely preserved, and the evolution of these features was highly complex. However, if we look at all the data we have, we can begin to work out the most likely appearance of particular dinosaur species.
Preserved feathers are primarily known from small theropods – such as the crow-sized Microraptor and wolf-sized Zhenyuanlong. This has been used to suggest that only small dinosaurs had feathers. However, large dinosaurs are rarely found in depositional environments capable of preserving feathers, meaning that this may be a false signal. Indeed, preserved feathers are known from the 9m tyrannosauroid Yutyrannus, proving that at least some large dinosaurs did have a coat of feathers.
Even where we don’t have direct evidence of feathers, indirect indicators exist. For example, even though no preserved soft tissues are known from Velociraptor, ‘quill knobs’ on its arm bones indicate that feathers were present. These lines of evidence show that feathers would have been widespread in coelurosaurian theropods – the group including tyrannosaurs, compsognathids, ornithomimosaurs, therizinosaurs, oviraptorosaurs, dromaeosaurs, troodontids and birds. However, much variety in the type, spread and presence of these feathers still exists. Tyrannosaurus itself is a good example: we know that its ancestors were feathered, but skin impressions from Tyrannosaurus and its close relatives such as Albertosaurus show areas both of naked skin, and scales. This shows that much of the body would have been scaly. However, it does not mean that feathers were completely absent.
These tyrannosaurids may have lost or reduced their feathers due to their large size – such big animals would have suffered heat stress if they retained a thick plumage. Yutyrannus lived in cold climates, and so would not have had these problems, and may have needed the extra insulation. In this way, it seems that although feathers appear to have been ancestral for – and widespread in – coelurosaurs, individual species may have altered, reduced or lost these feathers due to their size, ecology or environment.
Evidence of any kind regarding skin texture is very rare from other theropods, but includes extensive skin impressions from the abelisaurid Carnotaurus, which show that it was covered in scales. This suggests that feathers may have been rare or absent outside in non-coleurosaurian theropods, and so species such as Allosaurus, Spinosaurus and Acrocanthosaurus were probably scaly.
Looking at other dinosaurs, we have very little evidence of skin texture in sauropods, but those we do have are scaly. Comprehensive skin impressions are well-known from ornithopods and ankylosaurs, showing that they were scaly (and also that ankylosaurs were covered in armoured osteoderms). However, multiple smaller ornithischians are known preserving a variety of quill-like structures, showing that at least some heterodontosaurids, ceratopsians and other ornithischians carried quill-like structures. How widespread these were, and in what way they are related to the origin of feathers, is presently unclear. Unravelling this mystery will help us pin down when feathers originated, and how widespread they may have been in dinosaurs.
So, in summary, it seems that many dinosaurs were scaly, and this may be ancestral for the group. However, feathers were widespread in coelurosaurs, and may have also been present in other theropods – especially in small species. Still, it seems likely that feathers would have been reduced or lost in many larger theropods. Featherlike structures are also known from some ornithischians, but whether those represent early stages in feather evolution, or unrelated experiments in dinosaur integument is presently unknown. Unfortunately, data is lacking from many crucial dinosaur species. What we can say, though, is that dinosaurs were certainly very diverse in their skin texture and appearance.
Sauropods - how does do their necks work? Are they stiff like a giraffe or bendy like a crane? Does it vary be species?
I’ve seen various depictions of sauropod necks - from snake-like, to crane-like, all the way to more stuff like a giraffe. Does the flexibility of the neck vary from species to species to species? Are you able to give some answers on the flexibility of the neck on some sauropods like Brachiosaurus, Diplodocus, or Armargosaurus?
Most of the flexibility in a sauropod neck was at its base, with the remainder of the neck more limited. They were nowhere near as flexible as the body of a snake, due to the nature of their neck vertebrae – they were relatively long, and were braced by overlapping cervical ribs, limiting its flexibility. This, along with biomechanical constraints associated with their large size, also means that they would not have been able to perform the tight contortions that the necks of some modern birds, such as flamingos, can do. However, their necks were more flexible than that of a giraffe, as they were formed of many more bones – whereas a giraffe’s neck has only seven bones, those of sauropods could contain up to nineteen. Consequently, it is best to think of sauropod necks as, overall, somewhere between that of a giraffe and a crane in flexibility. Nonetheless, sauropod necks were very variable both in their overall length, depth and inclination; and in terms of the size and shape of the individual neck vertebrae: this varied in substantial differences in neck flexibility and posture between sauropod species.
The necks of mamenchisaurids and brachiosaurids, for example, were relatively stiff. The neck vertebrae sported long, overlapping ribs – these braced the neck against bending, but reduced its flexibility, particularly when trying to move from side-to-side. The neck of Brachiosaurus would have been carried relatively straight, in a roughly diagonal inclined posture – not flexed in a swan-like way as sometimes reconstructed. This compromise in lateral flexibility for the sake of stability emphasised the role of the neck as a tool maximising vertical reach, allowing Brachiosaurus to browse at the canopy level.
The necks of diplodocids – although also very long – were quite different. The cervical ribs were much shorter, allowing the neck greater side-to-side flexibility. However, the upwards flexibility of the neck appears to have been quite limited along most of its length, preventing it from being curved upwards – instead, up-and-down movements would have been made at the base of the neck. The necks of diplodocids could have been swept through the side-to-side direction and, to a lesser extent, upwards, allowing them to reach all around them. They could also supplement their vertical reach through rearing on their hind legs.
Dicraeosaurids, such as Amargasaurus, had very short necks for sauropod standards. Their neck vertebrae had both relatively short cervical ribs and were short overall, promoting flexibility from side-to-side and downwards. However, the large neural spines – especially in Amargasaurus and Bajadasaurus – would have constrained flexing of the neck upwards, as this would cause the spines to interlock. This, coupled with the overall short length of the neck, would have meant that dicraeosaurids would have been able to reach all around themselves for medium-high shrubbery, but would be unable to crane their necks to reach into high trees. Possibly the most flexible necks among sauropods belonged to rebbachisaurids, which had necks similar to those of dicraeosaurids, but they both lacked the tall neural spines and had also lacked some of the articulations found between the bones in the necks of other sauropods.
So, the necks of sauropods varied substantially between species in terms of both their overall dimensions, attitude and flexibility. This reflected, at least in part, feeding behaviour: neck anatomy indicates both the original browsing height and foraging strategy of sauropod species. The necks of some sauropods, such as brachiosaurids, primarily served to extend vertical height, whereas other, such as diplodocids, could be swept through horizontal and vertical arcs to reach through a large feeding envelope without having to move the body.
We’re going to wrap up part one of “The Science of Jurassic Park & More” there. Join us next week for part two – where David talks about new dinosaur discoveries, dinosaurs being able to swim, and much more!
For now, make sure to follow him on Twitter if you aren’t already, and stay tuned to The Jurassic Park Podcast for all the latest Jurassic Park news!