In terms of the general things the movie franchise gets wrong.
All of the theropods have their palms pronated down, but no theropod could biomechanically hold such a position without breaking or hyper extending their wrists. They should
be holding their hands with the palms facing each other.
In terms of sound, probably didn't sound anything like in the movies. Roaring is definitely out, as most tyrannosauroids didn't have the right kind of larynx to make that roaring sound. Think more sub-low rumbles, grunts, hisses, or booms. Plus, most tyrannosauroids were active predators, so roaring before you catch your prey is a bad move, lol.
In terms of integument, Jurassic Park isn't actually too bad for T. rex
, specifically. Most large tyrannosaurids like T. rex, Tarbosaurus, Gorgosaurus, Daspletosaurus, Lythronax,
we have skin impressions for, and they show scaly skin.
There was a paper by Bell et al. discussing why this could be the case, as with tyrannosauroid evolution, whether talking the more derived tyrannosaurids, or the more basal proceratosaurids show an overall increase in mass, length, and power. Considering the environments of the large tyrannosaurids, and their overall larger size, they hypothesize that maybe having down like feathers was selected against by their environment.
The above chart is a recording of fossil skin impression findings that was peer-reviewed by tyrannosauroid experts, and summarizes the paper I mentioned quite succinctly.
Of course, the largest proceratosaurid is Yutyrannus hauli
, and it's covered in filamentous feathers some 20 cm long from head to toe. But, while both Yutyrannus hauli
and Tyrannosaurus rex
are of the same kin, so to speak, they're actually not as close as say T. rex
For the raptors, or dromaeosaurids for the name of the whole group, Jurassic Park is showing its age.
Dromaeosaurids are maniraptorans, and the definition of a maniraptoran is having long hands with three fingers, and a semi-lunate, or half moon shaped bone in the wrist, which is the bone that allows birds (another type of maniraptoran) to fold their wings against their bodies.
On top of this, all fossil specimens of different kinds of maniraptorans all show quite derived feather covering, with the most derived feathers appearing in the deinonychosaurians (maniraptorans with a hyper-extended second toe claw), and the avialans, with avialans being the group that contains the ancestors of birds, and all birds.
For example, here's a fossil of Microraptor
, a small crow sized version of Velociraptor:
The arrows are pointing to the feather impressions. Near the end of the tail, we have a fan of feathers, on the legs we actually have wings, funnily enough, on the arms we have wings, and on the body and head, we have feathers too.
, specifically, we have quill knobs on its ulna that's almost identical to the quill knobs in modern birds:
The arrows are showing where those quill knobs are, showing where the feathers were anchored.
In terms for all deinonychosaurians, including dromaeosaurids, the morphology we should expect to see is illuminated by this fossil of Anchiornis
, a small troodontid.
Basically, we should expect to see feathers completely covering the head, around the eyes, but on the end of the snout, we should see reticulate scales, the arms should have quite derived pennaceous feathers, the legs and body should at least be contour feathers, the feet should be kinda like an eagle's foot, where you have scales that are basically feathers that turned into scales again, and on the tail, you should have a tail fan or frond, basically pennaceous feathers covering the tail too, or at least, on the end of the tail.
For larger dromaeosaurids, we actually have the same quill knob evidence on Dakotaraptor
, a large horse sized dromaeosaurid contemporaneous with Tyrannosaurus rex:
In terms of what the hyper-extended second toe claw is for, as that is, after all, what they're famous for, there was a study done by Fowler et al. discussing the purpose of it.
He noticed that the first digit, which is basically a dew claw, was roughly opposed to the rest of the digits, and since the second toe claw isn't really like a scythe blade, it doesn't have a cutting edge, but it's very pointy, and their biomechanics are roughly analogous to a bird of prey like a hawk or an eagle, in that they have enormous grip strength in their feet, he deduced that they might have ambushed the prey, pinned it down with their body weight while they dug their claws in to pin the prey down as they tore it apart alive.
Most non-avian theropod dinosaurs are characterized by fearsome serrated teeth and sharp recurved claws. Interpretation of theropod predatory ecology is typically based on functional morphological analysis of these and other physical features. The notorious hypertrophied ‘killing claw’ on pedal...
The above paper is free and open sourced, by the way.
In terms of speed, that's always a bit tricky for animals that's been dead for at least 65 million years. For large tyrannosaurids, namely T. rex
, estimates are around 15-25 mph, give or take, and for dromaeosaurids, around 25-35 mph, give or take.
seems more adapted to long-distance running though, due to the lovely named arctometatarsus, which is referring to a pinched middle metatarsal in the foot that acts a shock absorber.
If you look at the middle metatarsal of this T. rex
foot, it's squished between the other two metatarsals, which serves to make the structure of the foot more solid, allowing the animal to regain lost energy on the next step. It's basically a natural shock absorber.
On top of that, most tyrannosaurs have a large caudofemoralis longus muscle, which is a muscle that runs from the back of the femur to the middle of the tail. This is the main locomotor muscle in theropods, roughly homologous to our gluteus maximus muscle.
On top of that, most tyrannosaurs, T. rex
included, have really long legs. To be a strong runner in the dinosaur sense, you need nice long legs to increase the length of your stride, and powerful muscles. T. rex
has both of these in spades.
For dromaeosaurids, evidence points to the fact they're more ambush predators, considering fossil trackways showed that they held their second toe claw off the ground, meaning they walked on the outer two toes, and they lack the foot structure like T. rex
But, if Utahraptor
is anything to go by, they all have relatively robust foot structure in terms of grip, meaning that they likely ambushed the prey, pinned it down, dug the claws in and ripped the prey apart.
As far as T. rex
destroying a Jeep, that actually has semblance in reality. T. rex
is actually famous for having the strongest bite of any terrestrial animal, somewhere between 20,000-35,000 Newtons of force.
Which makes sense, since you find T. rex
teeth that are either buried in bone, or leave a tooth impression in some of the strongest bones of strong dinosaurs like Triceratops
pelvises, and apparently, according to a specimen of T. rex
, could bite a T. rex
tail clean off.
There was a famous study that said that T. rex's
bite was so powerful that it could pulverize bone. Not just crack it, pulverize
For raptors, their primary weapon was their limbs, so they didn't have as strong a bite as you would think. They mainly used their mouths for eating.
Anyhow, what I think should be improved is for Jurassic Park to make their T. rex
more robust, as it looks rather.... gracile compared to T. rex
Think more like this:
In terms of the dromaeosaurids, they should be covered head to tail in feathers and should be trying to pin prey down with their feet and rip them apart alive.
So dromaeosaurids should look and act like this:
There's more, but if I start discussing what's wrong with the other dinosaurs, namely Spinosaurus
, this would turn out to be unnecessarily long, lol.
Let me say this, the dinosaurs in the films don't look like dinosaurs, and Jurassic Park already has an explanation that they're genetic constructs, not true dinosaurs.
Accuracy though, the first movie's around a 6/10. The T. rex
is almost there, just not robust or muscular enough, and looks more like a Tarbosaurus
For the dromaeosaurids, that's why it's a 6/10, lol. They should be feathered.