The Stygimoloch and the Pachycephalosaurus may have been vegetarians, but they were aggressive dinosaurs! While they used their thick skulls as weapons, the Pachycephalosaurus earned a slight edge in battle.
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Battle Facts about Stygimoloch vs. Pachycephalosaurus
| Name | Stygimoloch, (Stygimoloch spinifer), Styx demon | Pachycephalosaurus, (Pachycephalosaurus wyomingensis), thick-headed lizard |
| Size | 6 feet long, 200 pounds | 16 feet long, 900 pounds |
| Speed | 8 mph | 7 mph |
| Offense | Pointed horns on its skull | Used its thick, heavy skull as a weapon |
| Defense | Has a very thick skull, powerful back legs | Bone on its skull that was 10 inches thick |
| Endurance and Behavior | Is very aggressive and territorial | Were very aggressive and traveled in large territorial packs |
The Stygimoloch and the Pachycephalosaurus were two very similar Pachycephalosaurs that lived in North America during the late Cretaceous period.
Even though they were herbivores (or plant-eating dinosaurs), they were surprisingly aggressive and often traveled in packs and fought over territory. With thick skulls and powerful back legs, these vegetarian dinosaurs were far from gentle giants.
How Similar Were the Pachycephalosaurus and the Stygimoloch?
The Pachycephalosaurus and Stygimoloch are members of Pachycephalosauria that lived during the late Cretaceous period and shared a lot in common.
These dinosaurs had a similar body type, ran on their powerful hind legs, and had a similar bone-headed skull. These paleontologists believe that they were the same dinos at different growth stages.
The Pachycephalosaurus and Stygimoloch are so similar that paleontologist Mark Goodwin and Jack Horner believe the Stygimoloch and the Dracorex are juvenile Pachycephalosaurus.
Both Pachycephalosaurs were upper cretaceous Hell Creek Formation dinos that lived in North America (Montana and South Dakota).
Who was Larger, the Stygimoloch or the Pachycephalosaurus?
The most significant difference between these very similar dinosaurs is their overall size. The Pachycephalosaurus was a much larger dino that measured 16 feet long and could weigh up to 1,000 pounds!
The Stygimoloch, on the other hand, was much smaller. It stood only 6 feet tall and weighed around 200 pounds (as much as a mature wolf).
Which Dino Was Stronger?
Not only was the Pachycephalosaurus bigger, but it was also stronger. Its powerful back legs allowed it to run fast, and its sharp front claws were for grabbing and slashing. While it looked like a plant-eating T-Rex, the Pachycephalosaurus was more closely related to a Triceratops.
Its large skull and powerful defensive abilities were more similar to the defensive head of a Triceratops or the Styracosaurus rather than an aggressive theropod like the Tyrannosaurus Rex or the Velociraptor.
Who Was Faster?
The Pachycephalosaurus was just a little faster. The Stygi could run about as fast as the average human, around 6 miles per hour. The Pachycephalosaurus, on the other hand, could reach top speeds between 7 and 11 miles per hour.
While the Pachycephalosaurus was faster, its larger size made it far less agile. Paleontology believes that the agile Stygimoloch could out-maneuver the Pachycephalosaurus if fleeing from a fight.
Who Would Win: the Stygimoloch or the Pachycephalosaurus?
It should be no surprise that the winner of this herbivore dino battle would be the Pachycephalosaurus! Not only was it bigger and faster than the Stygimoloch, but it also had a much thicker skull.
It would use its heavy skull to head-butt its target in battle and land a massive blow. Even though the Stygimoloch had a similarly thick skull, it was no match for the 10-inch thick head of the Pachycephalosaurus.
How did their defense work?
These bone-headed dinos use the ornaments (or bumps and knobs) on their skull as weapons and protect them. The bone knob on the crest of the Pachys skull measured to be about 10 inches thick.
To understand just how wide the Pachycephalosaurus skull was, it was about as thick as two soda cans stacked on each other!
With quick, agile speeds, and a built-in motorcycle helmet for a skull, these dinosaurs had plenty of protection from the aggressive dinosaurs in the late Cretaceous period.