CLOSE

10 Bone-Headed Facts About Pachycephalosaurus

Pachycephalosaurus’ domed, heavily-built head looks like it was capable inflicting some serious damage. Unfortunately, trying to decipher how this animal used that noggin has given many poor scientists headaches of their own.

1. Its Skull Roof was Up to 10 Inches Thick.

Pachycephalosaurus heads only reached total lengths of two feet or so. In case you’re curious, human men and women have an average skull thickness of 6.5 and 7.1 millimeters, respectively.

2. Pachycephalosaurus Heads Were Once Mistaken for Dinosaur Kneecaps.

Dinosaurs—unlike mammals—lacked kneecaps altogether. However, during the late 19th century, this fact wasn’t widely known, and few non-skull-related Pachycephalosaurus bones had been found, so this weird hypothesis is pretty forgivable.

3. One of its Close Cousins Has the World’s Longest Dinosaur Name.

Try saying this five times fast: Micropachycephalosaurus. It means “small, thick-headed lizard.” What a flattering label!

4. Pachycephalosaurus May Have Drastically Changed Shape with Age.

Dr. John R. “Jack” Horner—who, among other accomplishments, served as the Jurassic Park trilogy’s dino consultant—maintains that Pachycephalosaurus and two similar creatures which shared its habitat were really the same animal. Stygimoloch and Dracorex are smaller and had much flatter skulls. If Horner’s correct, these represent two juvenile stages of Pachycephalosaurus. He expands upon his argument at the 8:30-mark of this TED clip: 

5. It Belongs to the Same Dinosaur Clade as Triceratops.

Triceratops and its horned/frilled kin are collectively known as “ceratopsians.” Together with the pachycephalosaurids, they form a diverse dinosaurian group called the marginocephalia (“ridged heads”).

6. Perhaps Pachycephalosaurus Butted Heads.

Paleo-artists have traditionally drawn Pachycephalosaurus ramming headlong into each other musk ox-style. Does the available evidence support this?  Some scientists think so, claiming that their domes were well-equipped for absorbing such brutal impacts. Others, meanwhile, have their doubts.

7. … Or, Alternatively, Pachycephalosaurus Might’ve Preferred Flanking.

Today’s giraffes violently slam their heads into rivals’ sides. Maybe Pachycephalosaurus behaved likewise. Many of its kin had conspicuously-wide ribcages, which could theoretically withstand this sort of abuse. Also, try making two bowling balls forcefully collide at point-blank range. You’ll notice that the spheres will only briefly connect before quickly sliding apart thanks to their curvature. Pachycephalosaurus domes were also quite rounded and potentially faced the same mechanical challenge. If so, “flanking” might’ve been a more effective undertaking when tempers flared.

8. Pachycephalosaurus Had to Worry About T. rex.

Tyrannosaurus and Pachycephalosaurus both dwelled in western North America during the late Cretaceous period around 65 million years ago. That thick head was therefore possibly employed as an anti-predator weapon. 

9. Regardless, Pachycephalosaurus Could Sustain some Serious Cranial Trauma.

In 2012, paleontologist Joseph Peterson subjected a Pachycephalosaurus skull to CT scanning and found numerous potential injury marks “clustered over the thickest region of the dome,” which—in his view—seemingly corresponded with the head-butting hypothesis.

10. Pachycephalosaurus is (Indirectly) Linked to the Harry Potter Series.

To honor its dragon-like appearance and a certain best-selling book series, one new pachycephalosaurid species was named Dracorex hogwartsia in 2006. Upon hearing the good news, J.K. Rowling proclaimed “[this] is easily the most unexpected honor to have come my way since the publishing of the Harry Potter books! I am absolutely thrilled to think that Hogwarts has made a small claw mark on the fascinating world of dinosaurs.” She also added that “I can’t help but visualizing [Dracorex] as a slightly less pyromaniac Hungarian Horntail.”

But don’t get too excited, Potter fans. Remember: Dracorex could simply be nothing more than a young Pachycephalosaurus, which would make the Hogwarts-themed moniker obsolete. 

nextArticle.image_alt|e
iStock
arrow
science
The Clever Adaptations That Helped Some Animals Become Gigantic
iStock
iStock

Imagine a world in which eagle-sized dragonflies buzzed through the air and millipedes as long as kayaks scuttled across Earth. "Ick"-factor aside for bug haters, these creatures aren't the product of a Michael Crichton fever dream. In fact, they actually existed around 300 million years ago, as MinuteEarth host Kate Yoshida explains.

How did the prehistoric ancestors of today’s itty-bitty insects get so huge? Oxygen, and lots of it. Bugs "breathe by sponging up air through their exoskeletons, and the available oxygen can only diffuse so far before getting used up," Yoshida explains. And when an atmospheric spike in the colorless gas occurred, this allowed the critters' bodies to expand to unprecedented dimensions and weights.

But that's just one of the clever adaptations that allowed some creatures to grow enormous. Learn more about these adaptations—including the ingenious evolutionary development that helped the biggest dinosaurs to haul their cumbersome bodies around, and the pair of features that boosted blue whales to triple their size, becoming the largest animals ever on Earth—by watching MinuteEarth's video below.

nextArticle.image_alt|e
Wikimedia Commons/Public Domain
arrow
science
Feathers, Fighting, and Feet: A Brief History of Dinosaur Art
Wikimedia Commons/Public Domain
Wikimedia Commons/Public Domain

One of the first-known works of dinosaur art was The country of the Iguanodon, an 1837 watercolor by John Martin. It depicts the ancient reptiles as giant iguanas, thrashing and fighting near a stone quarry—a far cry from today's sophisticated 3D renderings.

By watching the PBS Eons video below, you can learn how our image of dinosaurs has changed over the centuries, thanks to artworks based on new scientific discoveries and fossil findings. Find out why artists decided to give the prehistoric creatures either feathers or scales, make them either active or sluggish, present them as walking on two or four feet, and to imagine tails that either dragged or lifted, among other features.

Keep in mind, however, that both emerging technologies and new findings are constantly changing the way scientists view dinosaurs. A new species, on average, is named every two weeks—and this research will likely keep artists busy (and constantly revising their work) for years to come.

SECTIONS

arrow
LIVE SMARTER
More from mental floss studios