The Real Dilophosaurus Makes the 'Jurassic Park' Version Look Tame

All of the non-avian dinosaurs were confined to a geologic era called the Mesozoic. This was divided into three periods: the Triassic, the Jurassic and the Cretaceous.

The latter went out with a bang; a mass extinction marked the end of the Cretaceous period 66 million years ago. Birds were the only dinosaurs who survived the catastrophe.

Their brethren had a good run. The earliest dinosaurs evolved around 243 to 231 million years ago during the Triassic period. A time of great reptilian diversity, the Triassic gave way to the Jurassic about 199 million years before the present.

Prior to that transition, most carnivorous dinos were small-bodied. Dilophosaurus was a sign of bigger things to come. The beast roamed what's now Southwestern North America early in the Jurassic period, about 183 to 193 million years ago.

Dilophosaurus measured over 20 feet (or 6 meters) long, making it the biggest known North American land animal alive at the time. Compared to many of the flesh-eating dinosaurs who'd existed beforehand, this thing was a giant.

So it's weird that the "Jurassic Park" Dilophosaurus is small enough to ride shotgun in actor Wayne Knight's jeep.

Knight played disgruntled computer programmer Dennis Nedry in the original "Jurassic Park" movie. After betraying his boss and endangering lives, Nedry gets his just deserts when a stray Dilophosaurus eats him in the front seat of a park vehicle.

The villain meets a similar end in Michael Crichton's "Jurassic Park" novel, of which the film is an adaptation. In the book, our protagonists are told: "Scientists thought [Dilophosaurus'] jaw muscles were too weak to kill prey, and imagined they were primarily scavengers. But now we know they are poisonous."

Stephen Spielberg's creative team gave their cinematic Dilophosaurus a cowl-like neck frill — similar to the ones modern frilled lizards use to scare enemies away. After unfurling this accessory, the little dinosaur makes like a spitting cobra and sprays venom into Nedry's eyes.

There's no evidence to suggest the real Dilophosaurus carried poison or venom — or had a movable neck frill. The toxic killer who slays Dennis Nedry has been described as "the most fictionalized of all Jurassic Park's dinosaurs."

But let's take another look at that quote from the novel. Crichton didn't pull the scavenger hypothesis out of thin air. Samuel P. Welles, the paleontologist who named Dilophosaurus in 1970, thought the creature might've had an affinity for eating carrion.

Below the dinosaur's nasal openings, you can see a distinctive notch on either side of its upper jaw. The "subnarial gap" (as this feature is called) lies at the meeting point of two separate jaw bones, both of which bear teeth.

Welles thought the notches implied these bones were weakly connected — and, therefore, Dilophosaurus didn't have a very strong bite. By the time Crichton's book came out, there'd been a lot of debate about this dinosaur's eating habits.

Pointing to the supposedly "weak" jaws, some experts suggested Dilophosaurus mainly ate corpses. Another hypothesis imagined Dilophosaurus as a fishing specialist that used its long teeth and jaws to snatch up wriggling fishes.

New research has cast the animal in a different light.

On July 7, 2020, the Journal of Paleontology published a study that reevaluated five specimens of Dilophosaurus. Co-authors Adam D. Marsh and Timothy B. Rowe found the maxilla-premaxilla connection was stronger than Welles had supposed. They also observed scaffold-like attachment points for strong muscles on the lower jawbones.

All this tells us Dilophosaurus actually had powerful jaws at its disposal. (Bite marks found on the remains of one Sarahsaurus — a large contemporary herbivore — may have been left behind by a peckish Dilophosaurus.)

Marsh and Rowe called more attention to the dino's trademark feature: its flashy head crests.

The name Dilophosaurus means "two-crested lizard." This is in reference to a pair of bony ornaments running down the creature's skull. It's unclear what the top of each crest looked like; scientists don't have any complete specimens to go on.

In their paper, Marsh and Rowe wrote that the crests were "almost certainly covered in keratin or keratinized skin." For the record, keratin is a fibrous protein found in hair, hooves, horns, fingernails, claws and other animal body parts.

Some modern birds — like the dangerous cassowary — have bony head crests 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've looked even more flamboyant than its naked skeleton might suggest.

If you're wondering what the dino's twin crests were for, join the club. Attracting mates is one popular explanation, though it's also possible the crests helped regulate body temperature.

Dilophosaurus' place on the tree of life is another big conversation topic. Pointing to shared anatomical features, Marsh and Rowe argued this dinosaur was related to two other crested predators: Zupaysaurus of Argentina and the Antarctic Cryolophosaurus.

One can see the footprints of large, predatory dinosaurs at Early Jurassic dig sites all over the world — from the Rocky Mountains to New England to eastern Europe. Some may have been left behind by Dilophosaurus itself.

Most of our Dilophosaurus knowledge comes from discoveries made on Navajo Nation land. In 1940, a Navajo man named 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 then took them to a Jurassic graveyard where three Dilophosaurus lay exposed.

Today, multiple specimens of this dinosaur — which legally belong to the Navajo Nation — are held in trust at the University of California Museum of Paleontology.

Samuel P. Welles had a long and fruitful career there before his death in 1997. As you'll recall, Welles was the person who gave Dilophosaurus its name. He was also one of those visitors Jesse Williams guided in 1942.

Welles proved you can appreciate a good dinosaur movie despite its scientific faults. After "Jurassic Park" hit theaters in '93, he didn't shy away from pointing out the Dilophosaurus-related inaccuracies.

Even so, Welles went on the record as saying, "I enjoyed the movie thoroughly and was very happy to find Dilophosaurus an internationally known actor."