Could Dilophosaurus Really Spit Poison?

OK, we're almost sure the answer is no. But there was a fossil-based reason that 'Jurassic Park' included this detail. Learn about the real-life Dilophosaurus in today's episode of BrainStuff, based on this article: https://animals.howstuffworks.com/dinosaurs/dilophosaurus.htm

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Episode Transcript

Speaker 1 (00:01):
Welcome to Brainstuff, a production of iHeartRadio, Hey brain Stuff
Lauren Vogelbaum here. Many of us first learned about the
Dilophosaurus through the Jurassic Park franchise. It certainly made them memorable.
In the novel by Michael Crichton from nineteen ninety these
dinosaurs spit a sort of gooey poison in the face

(00:24):
of prey to disable them, and the nineteen ninety three
film added bright red and yellow roughs or frills that
pop up from the creature's neck to surround its head.
The overall effect is scary and beautiful and unfortunately, or
perhaps fortunately, a completely made up As far as we know.

(00:45):
Dilophosaurus was, however, one of the few dinosaurs in Jurassic
Park that lived in the actual Jurassic Period. All of
the non avian dinosaurs were confined to the geologic era
called the Mesozoic. Divide the Mesozoic into three periods, the Triassic,
the Jurassic, and the Cretaceous, based on major changes that

(01:07):
informed the landscape and climate and life on Earth. The
Mesozoic era went out with a bang. A mass extinction
marked the end of the Cretaceous period. Sixty six million
years ago. Birds were the only dinosaurs that survived the catastrophe.
Their brethren had a good run, though. The earliest dinosaurs

(01:28):
evolved around two hundred and forty three to two hundred
and thirty one million years ago during the Triassic Period,
a time of great reptilian diversity. The Triassic gave way
to the Jurassic about one hundred and ninety nine million
years before the present. Prior to that transition, most carnivorous
dinosaurs were small bodied. Dilophosaurus was a sign of bigger

(01:51):
things to come. The beast roamed what was now southwestern
North America in the early Jurassic period about one hundred
and eighty three to one hundre undred and ninety three
million years ago. Dilophosaurus measured over twenty feet long or
six meters, making it deep biggest known North American land
animal alive at that time. Compared to many of the

(02:13):
flesh eating dinosaurs that had existed beforehand, this thing was
a giant that first Jurassic Park film portrayed Dilophosaurus as
being smaller small enough to ride shotgun in a jeep.
As a matter of storytelling practicality, they wanted to distinguish
it from their larger velociraptors, especially because they were the

(02:34):
main dino antagonists that poisoned. Spit becomes a flashy, if
gory plot point in the novel and the film when
one of the human antagonists meets his just desserts. The
book explains scientists thought Dilophosaurus's jaw muscles were too weak
to kill prey and imagined they were primarily scavengers, but

(02:55):
now we know they are poisonous. There's no evidence to
suggest that the real Dilophosaurus had a movable neck frill
or carried poison or venom. Generally speaking, the difference between
poison and venom is that venom is injected into a
victim's flesh through a stinger, spines, teeth, or claws, whereas

(03:15):
poison is applied more indirectly and absorbed through the victim's skin, airways,
or digestive system. These evolved delivery methods have to do
with the chemical composition of an animal's toxins. Poisons are
made up of tiny molecules that can see right past
the tight barrier of the skin into the victim's body.

(03:37):
Venoms are made of larger molecules. That are too big
to do that, so they have to be introduced via
a wound. All of this would give you the idea
that a fictional Dilophosaurus spitting would be poisonous, except that
it mimics the real life modern spitting cobras, which are
venomous snakes that have adapted the ability to spit their

(03:58):
venom into a victim's face, where the mucous membranes of
the eyes, nose, and mouth allow the venom to penetrate
into the body. All of that being said, a toxin
spitting Dilophosaurus is fictional, so the technicality of venomous versus
poisonous doesn't really matter. However, just because this adaptation is fictional,

(04:20):
it doesn't mean that Michael Crichton pulled the scavenger hypothesis
out of thin air. The paleontologist who named Dilophosaurus in
nineteen seventy won, Samuel P. Wells, thought the creature might
have been mostly a carrion eater. Below the dinosaur's nasal openings,
there's a distinctive notch on either side of its upper jaw.

(04:42):
These notches lay at the meeting point of the toothy
upper and lower jaws, and Wells thought the notches implied
that these bones were only weakly connected, and therefore the
Dilophosaurus didn't have a very strong bite. By the time
Crichton's book came out, there had been a lot a
lot of debate about this dinosaur's eating habits. The carrion

(05:04):
concept was one hypothesis. Another imagined Dilophosaurus as a fishing
specialist that used its long teeth and jaws to snatch
up wriggling fish. But since then, new research has cast
the animal in a different light. In twenty twenty, the
Journal of Paleontology published a study that reevaluated five specimens

(05:25):
of Dilophosaurus. The authors found that the connection between the
upper and lower jaws was stronger than Welles had supposed,
with scaffold like attachment points for stronger muscles on the
lower jawbones. This suggests that Dilophosaurus actually had powerful jaws
at its disposal, and bite marks found on a large

(05:46):
contemporary herbivore seemed to match Dilophosaurus. The researchers also called
more attention to the dinosaur's trademark feature, its flashy headcrests,
less flashy than a pop up neck work, but the
name Dilophosaurus means two crested lizard. The creature had a
pair of bony ornaments running up along its skull like

(06:09):
a double mohawk. It's unclear what the top of each
crest looked like. Scientists don't have any complete specimens to
go on, but the researchers wrote that the crests were
quote almost certainly covered in keratin or carotenized skin, Keratin
being the fibrous protein that makes so many animal body

(06:29):
structures so tough, like hair, hoofs, horns, fingernails, claws, beaks,
and feathers. Some modern birds, like the dangerous casswary, have
bony headcrests sheathed in a layer of keratin based material.
These coverings can make the crest as a whole significantly
taller than the underlying bone. So who knows. Dilophosaurus could

(06:54):
have looked even more flamboyant than its naked skeleton might suggest.
But if if you're wondering what the animal's twin crests
were for, join the club. Attracting mates is one popular explanation,
though it's also possible the crests helped regulate body Temperaturesaurus
knowledge comes from discoveries made on Navajo Nation land. In

(07:17):
nineteen forty, a Navajo man by the name of Jesse
Williams became the first person in recorded history to lay
eyes on a Dilophosaurus skeleton. Two years later, a group
of visiting scientists contacted Williams. He took them to a
Jurassic graveyard where three Dilophosaurus lay exposed. Wells, who would

(07:37):
name the animal and inspire criton's spitters, was one of
those scientists. Today, multiple specimens of this dinosaur, which legally
belonged to the Navajo Nation, are held in trust at
the University of California Museum of Paleontology. But you can
see the footprints of large predatory dinosaurs at early Jurassic

(07:58):
dig sites all over the world, but from the Rocky
Mountains to New England to eastern Europe. Some may have
been left behind by Dilophosaurus. Connecticut chose this dinosaur as
its official state dinosaur in twenty seventeen after trackways made
by an unidentified meat eating dinosaur from the early Jurassic
were found there. It's certainly possible that Dilophosaurus or a

(08:22):
close relative was the predator in question. Samuel P. Wells
had a long and fruitful career before his death in
nineteen ninety seven. After Jurassic Park hit theaters in ninety three,
he didn't shy away from pointing out the Dilophosaurus related embellishments.
Even so, Wells went on the record as saying I

(08:45):
enjoyed the movie thoroughly and was very happy to find
Dilophosaurus an internationally known actor. Today's episode is based on
the article the real Dilophosaurus makes the Jurassic Park for
and look tame on HowStuffWorks dot Com, written by Mark Mancini.
Brain Stuff is production of iHeartRadio in partnership with HowStuffWorks

(09:07):
dot Com and is produced by Tyler Klang. But four
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