Temporal range: Late Cretaceous
An artist's illustration of Pachycephalosaurs wyomingensis
Scientific classification
Kingdom: Animalia
Phylum: Chordata
Order: Ornithischia
Family: Pachycephalosauridae
Tribe: Pachycephalosaurini
Genus: Pachycephalosaurus
Brown & Schlaikjer, 1943
Species: P. wyomingensis
Binomial name
Pachycephalosaurs wyomingensis
Gilmore, 1931

Pachycephalosaurus/Tylosteus is a genus of pachycephalosaurid dinosaurs. It lived during the late cretaceous in what is now North America. Remains have been excavated in Montana. It was an herbivorous creature which is only known from a single skull and a few extremely thick skull roofs. Pachycephalosaurus lived 68-67 mya.

Description Edit

Pachycephalosaurus skull

A cast of the only Pachycephalosaurus skull

Pachycephalosaurus was probably bipedal and was the largest known of the bone-headed dinosaurs, with some others being Stygimoloch, Dracorex, and Stegoceras. It is famous for having a large, bony dome atop its skull, up to 25 cm (10 inches) thick, which safely cushioned its brain. The dome's rear aspect was edged with bony knobs and short bony spikes were projected upwards from the snout. These features suggest that, despite their bipedal stance, they were likely to have been relatives of the ceratopsians.

Using data from other pachycephalosauridae, it has been estimated that Pachycephalosaurus was approximately the length of a large car, maybe around 4.6m long (15 feet) and had a fairly short, thick neck, short fore limbs, a bulky body, long hind legs and a heavy tail, which was likely to have been held rigid by ossified tendons. Large eye-sockets that faced forward suggest that the animal had good vision and was capable of binocular vision.

Pachycephalosaurus scale

Estimated scale between a Pachycephalosaurus adult and a human

Lifestyle Edit

Scientists once suspected that Pachycephalosaurus and its dome-headed relatives were the bipedal equivalents of the big-horned sheep of today. It was thought that, in the mating season, big males would run at one another, clashing heads to decide which would dominate and mate with a herd of females. It was also thought that they might have used their domed heads for defence against predators. However, it is now believed that the Pachycephalosaurs would not have used their domes in this way so much. The adult head bones could not adequately have withstood pressure and impact and the skulls lacked proper shock absorption like Big Horned Sheep, and it's more likely that they head-butted their sides, to try to knock them off balance. Also, there is no evidence of scars or other damage on fossilized Pachycephalosaurus skulls. On the other hand, it's unlikely that pachycephalosaurs developed those thick skulls for display alone. It's a rather opinionated discussion.
Pachycephalosaurus skull

Adult skull in two perspectives

Scientists do not yet know what these dinosaurs ate. Having very small, ridged teeth they could not have chewed tough, fibrous plants as effectively as other dinosaurs of the same period. It is assumed that pachycephalosaurs lived on a mixed diet of leaves, seeds, fruit and insects. The sharp, serrated teeth would have been very effective for shredding plants.

In The MediaEdit

  • Pachycephalosaurus appeared in the 1997 film The Lost World: Jurassic Park stampeding with the other dinosaurs. One of them appeared in the 2015 film Jurassic World But they appeared to be fully grown.

    The Lost World: Jurassic Park Pachycephalosaurus

  • Three Pachycephalosaurus attack Cera in The Land Before Time they returned again in the 4th Land Before Time movie when they fight each two and Petrie gets dizzy to see them fighting but in the later movies they lived in the Great Valley.
  • Pachycephalosaurus appeared in the 35th episode of Dink, the Little Dinosaur & one of them was a new but minor character named Nobby.
  • An Dinosaucer Pachycephalosaurus named Bonehead appears in Various episodes of Dinosaucers, Bonehead can sometimes Devolve into his ancestral appearance.
  • Some Pachycephalosaurus appeared in a few episodes of Kong: The Animated Series. One of them was also seen briefly on the Film Kong Return to the Jungle.
  • In Dinozaurs There's a character named Dino Pachy his dinosaur form is a Pachycephalosaurus and his Dino Weapon mode is the Pachy Spike Sword.
  • A Pachycephalosaurus appeared in a few episodes of Dinosaur King.
  • Pachycephalosaurus is the title of a song on a 2006 album by the band Showbread, entitled Age of Reptiles.However,despite its name,the song itself doesn't have something to do with the dinosaur.
  • The Transforme

    Primeval: New World Pachycephalosaurus

    rs characters of Hardhead and Dinotron turned into Pachycephalosaurus.
  • A Zord in Power Rangers: Dino Thunder was based on Pachycephalosaurus, and another in Power Rangers: Dino Charge.
  • It is a huntable species in Carnivores.
  • Pachycephalosaurus appears in Anime film Age of the Great Dinosaurs with one being the victim of the one-eyed Tyrannosaurus rex.
  • A juvenile Pachycephalosaurus is hunted by two Troodon in Dinosaur Revolution. It is the model of the scrapped Prenocephale.
    Jurassic world pachycephalosaurus by sideswipe217-d8qhkv9

    Jurassic World Pachycephalosaurus

  • Pachycephalosaurus appears in Two National Geographic Documentaries Bizarre Dinosaurs & in Dinosaurs Decoded, where Jack Horner talks about how Stygimoloch and Dracorex are actually young Pachycephalosaurus, however, not many people agree with this, and the idea has mostly been rid of.
  • In Pokemon series, Cranidos and its evolved form Rampardos are based on Pachycephalosaurus. These two Pokemon were first introduced in the video games, Pokemon Diamond & Pearl.
  • Pachycephalosaurus will be in the upcoming game Saurian as a playable dinosaur.



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