- "A Pachy... a pachy... oh, hell. Uh, the fathead with the bald spot. Friar Tuck!"
- —Roland Tembo(src)
Pachycephalosaurus is the last, largest, and most famous member of the Pachycephalosauria, or thick-headed dinosaurs. In the 1970s paleontologist Peter Galton proposed that male pachycephalosaurs used their dome heads as battering rams, like Bighorn sheep. The idea caught the public's imagination, and two individuals are seen doing this in The Lost World: Jurassic Park (of course, these are genetically engineered dinosaurs and not necessarily exactly the same ones that lived 70 million years ago!). But by the 1990s, scientists began to question Galton's head butting theory. It was pointed out that animals who do butt heads have a wide surface area where the heads come into contact to prevent "head slippage." This happens when two animals butt heads at high speed and do not hit straight on. The risk breaking their necks when their heads suddenly snap to one side. Pachycephalosaurus has a domed, or rounded, head, which would minimize surface contact and therefore increase the risk of head slippage. This throws doubt on the idea of any high speed head-butting between pachycephalosaurs, but it does not exclude "head-pushing" of "head-ramming" against non-pachycephalosaurs.
Their skin was mostly dark brown with a white underbelly and with dark blue markings.
Wild on Isla Sorna
When Hurricane Clarissa hit Isla Sorna, the InGen workers evacuated the island. The Pachycephalosaurs were either freed by the fleeing workers or broke free themselves. From this point on the Pachycephalosaurs and many of InGen's dinosaurs integrated themselves into Isla Sorna's ecosystem. To fight the Lysine contingency, they would eat Lysine rich plants.
Pachycephalosaurus was known to have lived in the island's south.
During the game trail harvest, the InGen hunting team captured a Pachycephalosaurus on the Game Trail. It was nicknamed "Friar Tuck" because their leader Roland Tembo was unable to pronounce its genus name.
In the struggle, the creature briefly managed to escape and charged forward at a hunter taking cover behind a car door. The Pachycephalosaurus knocked one hunter aside as it went, and realizing what was about to happen, the other hunter tried to take shelter in his jeep. Unfortunately, the animal slammed into the car door before the man could pull his legs into the car, crushing his legs in the door in the process. The Pachycephalosaurus was eventually subdued and captured by the hunting team.
- "Why are the west plains closed? "
"Another Pachy roaming outside its zone."
- —Claire Dearing and Vivian Krill(src)
A new set of clones was created by InGen for Masrani Global Corporation's Jurassic World. These new clones were close to the size of the originals. The new clones' skin was dark red with lime spots and a lime underbelly. They resided in the self-titled Pachy Arena where visitors could watch them have on of their famous head-butt duels. Everytime they butt heads, their inplants became temporarily disabled, which allowed the Pachycephlosaurs to escape the Pachy Arena without being tracked. It is unknown as to why the website Pachycephalosaurus look very different from their original cloned counterparts, as in the security camera, the Pachycephalosaurus looked very different.
While not in the film, it has been revealed that there were surviving Pachycephalosaurus populations on Isla Nublar, but as none were seen being taken to Lockwood Manor, it can be assumed the species has fallen back into extinction.
It is possible that Pachycephalosaurus was saved offscreen. 
Pachycephalosaurus first appeared in The Lost World when Levine and Malcolm were in the high hide viewing all of the dinosaur herds across the valley. The herd was quite large, consisting of about a dozen members if not more, and was first located to the south of the valley, the herd was often found in the middle of the island's roadways where they would congregate and take advantage of the mudholes in the road, usually to the distress of people having to use the roads in their cars. Levine was unsure whether they were Gravitholus albertae or Pachycephalosaurus wyomingensis at first but he eventually decided they were the latter. Levine and Malcolm were at odds over the issue that the animals butted heads. They are described as being 4–6 feet tall, dark-green, having large curved protruding foreheads, a rim of knobby horns, and having the overall demeanor of African Buffalo. They usually stood in a lazy, contented, cow-like manner unless disturbed, in which case they would attempt to ram things with their domed skulls.
Howard King came around a corner, and saw a herd of animals in the road. They were some kind of green dinosaur, about 4 ft tall, with big domed heads and a bunch of little horns, that smooth bulging curve on the forehead and all those little horns. The front bumper nudged the nearest animal, which grunted, took a couple of steps back, lowered it's head and butted the front of the car with a metallic clang! He opened the door, and climbed out, the animals jumped to their feet and the nearest one charged him. He had the door open; the animal smashed into it, slamming it shut, leaving a deep dent in the metal. He ran around the back of the car, just as another smashed into the rear taillight, shattering the plastic. A third animal charged the back of the car directly. King scrambled up onto the spare tire, as it slammed into the bumper. The jolt knocked him off, and he fell to the ground, rolling while the Pachycephalosaurus snorted all around him.
"Is Levine there?" The radio clicked. Harding said, "Ask him if there's any danger from a green dinosaur that's about 6 ft tall and has a domed forehead." Levine nodded. "Tell her yes. They're called Pachycephalosaurus" "Why?" "Because there's about 50 of them all around the car."
Now the puddle had become a mudhole, thanks to the dozen or so animals that sat in it. These were the green dome-headed that she had been watching. She had watched the Pachycephalosaurus with uneasiness. "Levine says nobody knows anything about these animals, Sarah" "Great," she said. "Levine says a complete skeleton has never been recovered. So nobody has even a guess about their behavior, except that they're probably aggressive."
Suddenly one of the animals charged the trunk of the tree she was in, butting it hard. The impact was surprisingly forceful. She struggled to hold on. Oh shit, she thought. Then she hit the ground, right beside the animals.
Sarah Harding was underneath the car, and now she was staring out at the animals' feet. The pachys were stamping and snorting, Trying to get at her under the car. The nearest pachys snorted and banged on the bumper. They leaned down and twisted their heads, trying to get to her. "They have very bad breath," she said. Suddenly, they all thundered off.
Pachycephalosaurus is depicted to be territorial, meaning that they will attack if the player/other dinosaurs were inside their territory. They're not a strong enemy as they can be easily killed.
In this game, you will be sitting in your car, and a bunch of Pachycephalosaurus will charge you. In order to defeat them, you will have to shoot their body, shooting their bone-head wouldn't be effective. They sometimes come often.
Pachycephalosaurus is encountered in the Human Hunter and Velociraptor levels. The Pachycephalosaurus is bigger than the ones seen in the film, furthermore suggesting that they were not fully grown in the film. Like in the arcade game they can only be hurt if hurt/shot in the body.
Pachycephalosaurus is an unlockable dinosaur in Warpath: Jurassic Park. Its skills are the same as Stygi, and its stage its the Mountianous Steppes. Its colors are emerald/cinnamon, emerald/goldenrod. and amber. Although its weight scale is at the wrong number in the museum, the announcer says its correct weight.
Jurassic Park: Operation Genesis
Pachycephalosaurus is a two-star small herbivore, at closer to its correct length than those of the movie. It is the primary dinosaur that the player must create to endorse more new dinosaurs. It will fight against each other although they never seriously injure each other. They also use their hard heads to attack small carnivores (except Albertosaurus). They are friends with the Homalocephale.
The coloration is very close to The Lost World Pachycephalosaurus, with the only exception being a little bit of red on the dome.
Pachycephalosaurus is nr 092 of the Herbivore Twos that can be created in Jurassic Park III: Park Builder.
"Pachycephalosaurus is the eighth dinosaur species encountered in JPIII: The DNA Factor. In the level Perilous Highlands, it appears strong enough to smash large boulders that block the player's path by ramming them.
Pachycephalosaurus is available to purchase as your sixth dinosaur in the game.
Pachycephalosaurus is one of the available dinosaurs on the IOS application, Jurassic World: The Game. Since September 30th 2015, a fully maxed Pachycephalosaurus could be mixed with Nasutoceratops to make a Pachyceratops.
Pachycephalosaurus will appear in Jurassic World: Evolution. It seems to be based on the Lost World design.
Two figures of Pachycephalosaurus, one a juvenile and the other an adult with the color scheme of the Pachycephalosaurs seen in The Lost World: Jurassic Park, were made for The Lost World Series 1 toy line.
A repaint of the Pachycephalosaurus from The Lost World Series 1 is packaged with a Dino Trainer in the Jurassic Park: Dinosaurs toy line.
A Pachycephalosaurus figure is a part of the Jurassic World toy line. It is categorized under the "Bashers and Biters" assessment.
Three new figure of Pachycephalosaurus were released as part of the toyline for Jurassic World: Fallen Kingdom. One was released as part of the Basic Dinosaurs line, another was released in the Legacy Collection line, and one was part of the Battle Damage line. The Legacy Collection Pachycephalosaurus is styled after the Pachycephalosaurus seen in The Lost World: Jurassic Park, while the Battle Damage Pachycephalosaurus is based on its appearance on the Jurassic World website.
Behind the scenes
Interestingly, in the script for The Lost World: Jurassic Park, the identity of Pachycephalosaur captured by the Hunters was more vague as Burke initially identifies it as Pachycephalosaurus but afterward later identifies the animal as either once again being Pachycephalosaurus or Prenocephale.
The practical effect of the Pachycephalosaurus seen in The Lost World: Jurassic Park was sculpted and painted by Scott Stoddard and was mechanized by Jeff Edwards and Rich Haugen. There were three versions that created and employed for use in the film. These three variants were a full-sized hydraulic puppet, an insert head, and an animatronic of the Pachy in a ramming stance for when it headbutts one of the vehicles of the InGen Hunters.
Pachycephalosaurus was the only dinosaur in the Round Up scene that was not purely portrayed with CGI with an animatronic being used in close up shots.
In The Lost World (the only movie in which it vocalized), the Pachycephalosaurus consisted several vocalizations which some sounded much aggressive or ominously threatening. The vocals are portrayed as raspy or blunt consisting of squawks or bleats from both Vultures, Sheep, Goats; and moans from a Camel and Rhino.
- ↑ Dinosaur Field Guide, page 102, 103.
- ↑ Pachycephalosaurus is not seen on the Jurassic Park brochure.
- ↑ Thermal scan of Isla Sorna in The Lost World: Jurassic Park during Ian Malcolm's and John Hammond's discussion about Site B.
- ↑ 4.0 4.1 Jurassic World
- ↑ https://twitter.com/colintrevorrow/status/1037978176587218944
- ↑ The Lost World Film Script - Scene 42: Back in the Container Truck
- ↑ The Making of The Lost World: Jurassic Park, p. 49
- ↑ The Making of The Lost World: Jurassic Park, p. 88
|The Lost World: Jurassic Park Dinosaurs|
|Compsognathus • Edmontosaurus • Gallimimus • Mamenchisaurus • Pachycephalosaurus • Parasaurolophus • Pteranodon • Stegosaurus • Triceratops • Tyrannosaurus rex • Velociraptor|
|Jurassic World Dinosaurs|
|Ankylosaurus • Apatosaurus • Dimorphodon • Gallimimus • Indominus rex • Mosasaurus • Parasaurolophus • Pteranodon • Stegosaurus • Triceratops • Tyrannosaurus rex • Velociraptor|
|Playable Warpath Dinosaurs|
|Acrocanthosaurus • Albertosaurus • Ankylosaurus • Carcharodontosaurus • Cryolophosaurus • Giganotosaurus • Megaraptor • Pachycephalosaurus • Spinosaurus • Stygimoloch • Styracosaurus • Suchomimus • Triceratops • Tyrannosaurus rex|