In the
immensely popular movie Jurassic Park, there’s the famous scene where the giant T-Rex is
attacking a jeep during a thunder storm.
As it attacks, Dr. Alan Grant, a self-respecting paleontologist, yells, “Don’t move!
He can’t see you, if you don’t move.”
Here’s the thing - that's wrong.
(If that comes as a blow, you're definitely not going to want to learn the shocking truth
about Velociraptors we’ll get into in the Bonus Facts in a bit.)
The Tyrannous Rex not only could see just fine, whether the object was moving or non-moving
(which helps one not run into a huge number of things that exist in the world), there's
also quite a bit of evidence that the T-Rex’s sight was extremely good, very possibly better
than modern-day hawks and eagles.
This is perhaps unsurprising considering that birds are coelurosauri theropods, which is
the same sub-group that the Tyrannosaurus belongs to.
In fact, one of the T-rex’s closest living relatives is the chicken…
Going back to the film, this non-moving "fact" from the hit 1993 movie inspired a good deal
of research into the subject after.
Professor Kent Stevens at the University of Oregon began the project DinoMorph in 1993.
His goal was to develop “a means to create scientifically useful yet simplified digital
models of dinosaur skeletons.”
Using digital technology, he wanted to recreate tangible visualizations of extinct animals,
including the T-Rex.
After speaking at a conference in Toronto in June 1993 (the movie was released in the
US on June 11, 1993), he paid a visit to the Royal Ontario Museum where he met with North
America’s leading paleoartist, Garfield Minott.
He was working on a life-size “reconstruction” of a Tyrannosaurus Rex and provided Stevens
with life-like head sculptures of seven different theropods (bipedal and primarily carnivorous
dinosaurs), including a T-Rex and Velociraptor.
Using these models, a laser pointer, a glass plate, and taxidermic glass eyeballs, Stevens
performed experiments to determine the visual field, depth perception, and binocular range
(the area that can be viewed at the same time by both eyes) of these dinosaurs.
He published the results in 2006.
Performing a test called “inverse perimetry,” Stevens evaluated how well a T-Rex would be
able to see objects at various elevations and shapes.
To quote him, the wider an animal’s binocular range is, “the better its depth perception
and capacity to distinguish objects--even those that are motionless or camouflaged.”
Stevens determined that a T-Rex’s binocular range was 55 degrees, which is wider than
even hawks.
Stevens continued the research with other theropod dinosaurs and determined that most
theropods had binocular ranges at least similar to modern raptorial birds (aka “birds of
prey”).
Another recent discovery also confirmed that vision was an important sense for the T-Rex,
as scientists determined that the T-Rex’s snout over time gradually grew longer, narrower,
cheek bones dipped more inward, and their eyeballs grew bigger.
While structurally the T-Rex’s head and eyes seem primed for great vision, the question
remained- how good were their eyes really?
For that, Stevens took the known optics of distant relatives of the T-Rex, including
the eagle, chicken, and crocodile, and plugged them into the larger T-Rex eyeball.
He was trying to determine visual acuity (clearness of vision) and the greatest distance an object
can be seen that still remained distinct.
According to his findings, while admitting that these were best-case scenario determinations,
the T-Rex may well have had visual clarity up to 13 times better than a modern human.
For reference, an eagle has about 3.6 times the visual clarity of a person.
Additionally, it was determined that a T-Rex’s vision allowed an object to remain relatively
clear up to six kilometers away.
For humans, it's only about 1.6 kilometers for the same clarity.
As Stevens put it, “With the size of its eyeballs, (the T-Rex) couldn't help but have
excellent vision."
Of course, in the movie (and to a greater and more detailed extent in the book), it
is stated that in order to bring these dinosaurs back to life, the scientists needed more DNA
to fill the “gaps”.
In the book, they decided to splice dino DNA with bird, lizard, and frog DNA.
In the movie, they only use frog DNA to hammer home the plot device that certain species
of frogs can change sex when there is significantly less of one sex in the wild.
So given this, it may be that the dinosaurs in the movie are more frog than actual historic
dinosaurs.
So, if that’s the case, while a bit of a stretch, the question that can be asked is,
"Was the statement made by Dr. Grant in the movie actually more about a frog’s vision
than a T-Rex’s?"
Digging a tad deeper, this quote from the movie by Dr. Grant gives us a clue to what
species of frog they may have used: “They mutated the dinosaur genetic code and blended
it with that of a frog's.
Now, some West African frogs have been known to spontaneously change sex from male to female
in a single sex environment.”
The most common West African frog that has a tendency to change gender is the African
reed frog.
These frogs see quite on par with other species of frogs with their horizontal pupils, though
they cannot see in the red spectrum.
Yes, it is documented that frogs have a hard time seeing prey that doesn’t move, but
not significantly so, such that they'd be blind to them.
Plus, humans (and really, all other prey) do move even when they think they are standing
still- breathing, trembling, involuntary jerks, this is all movement.
Additionally, as Kent Stevens said in response to this moving myth question, "If you're sweating
in fear one inch from the nostrils of the T. Rex, it would figure out you were there
anyway."
Besides great vision, the T-Rex also had a great sense of smell (and had good hearing).
In fact, their large olfactory bulbs and nerves relative to their brain size indicates they
may have had a sense of smell about equivalent to modern vultures, which are able to smell
dead things from as far away as a couple kilometers.
So whether scavenging or hunting, the T-Rex was good at finding things to eat.
That said, there is some debate as to just how fast they were, with most scientists today
thinking they had only a max speed of about 17-25 mph.
In the film itself, the character of John Hammond states, “Well, we clocked the T-rex
at 32 mph”.
Even at that speed, it would have made the jeep chase scene quite a bit less dramatic
than what was depicted.
Speaking of learning things to help you spot errors in films and
thereby making you look smart
to all your friends, Brilliant!!!
Bonus Fact: If you thought that Velociraptors were slightly
bigger than a human; reptilian looking; hunted in packs; were found in what is now the United
States; were ridiculously intelligent, and had a thing for Chris Pratt, Well, literally
none of that is true, except the last one…
Who doesn’t love Star Lord?
In truth, velociraptors were actually only about the size of a domesticated Turkey, being
only about 3 feet tall and 6 feet long, with most of the length coming from the tail and
weighing in at around 20-30 pounds full grown.
More than that, they also looked somewhat like a Turkey as well, but with a long tail
obviously.
It turns out, Velociraptors were very similar to birds in a lot of ways.
They had hollow bones, feathers, built nests for their eggs, and are thought to have behaved
very similar to birds.
As Mark Norell, curator of fossil reptiles, amphibians, and birds at the American Museum
of Natural History, stated, “The more that we learn about these animals the more we find
that there is basically no difference between birds and their closely related dinosaur ancestors
like Velociraptor.
Both have wishbones; brooded their nests; possess hollow bones; and were covered in
feathers.
If animals like Velociraptor were alive today, our first impression would be that they were
just very unusual looking birds."
More than that, it is generally thought that Velociraptors were solitary creatures, rather
than hunting in packs as depicted in the films.
Next up, the Velociraptors were not found in the United States, as the films suggested:
where the paleontologists in the film dug up the Velociraptor skeleton in Montana.
In fact, they are typically found in Central Asia around Mongolia.
Were they intelligent?
Well, for a dinosaur, it is thought they were somewhat intelligent due to their brain size
relative to body size, but it’s not thought they were particular intelligent overall,
and certainly not "smarter than dolphins, whales, and some primates" that Dr. Alan Grant
in Jurassic Park III suggests.
So what were they thinking in Jurassic Park?
Well basically, they modeled what they called the "Velociraptor" in the movie after the
Deinonychus.
The Deinonychus were also raptors, but were significantly bigger than the Velociraptors,
coming in at about 12 feet long, about 6 feet tall, and weighing about 150 pounds full grown.
Pretty much picture the "Velociraptor" in Jurassic Park and you get a good idea of what
the Deinonychus were thought to have looked like (although likely with feathers.)
The Deinonychus also were thought to have occasionally hunted in packs to bring down
larger prey and were thought to have been very fast.
Their habitat was in the forests of North America.
Now on the intelligence bit, they too weren't really thought to have been very intelligent
relative to dolphins, primates, and the like.
Although, clearly they were at least smart enough to work together to bring down larger
prey when the need arose.
As to why the Velociraptor name was used even though the creatures were loosely based on
deinonychus, according to Michael Crichton, this was simply because the velociraptor name
was, to quote, “more dramatic”.