Thanks to its similar-sounding name, today’s dino will always get mixed up with the spiky-tailed, crowd-pleasing Stegosaurus. If you caught these two standing side by side, however, you’d have no trouble telling them apart. Bipedal Stegoceras had a very different profile and led a very different lifestyle. 

1. Its Back Legs Were Three Times Longer Than Its Front Ones.

Stegoceras probably didn’t win many arm wrestling contests with those “short and weak” forelimbs.

2. A New Species Was Introduced in 2011.

Seventy-two million years ago, Stegoceras novomexicanum roamed the American Southwest. At around four feet long, it would have been dwarfed by Stegosaurus validum, a better-known species which measured in at just over six feet from end to end.

3. Stegoceras’ Name Means “Horned Roof.”

Coined by paleontologist Lawrence Lambe in 1902, the moniker references that bumpy dome on the dino's head.

4. The Creature Was a Heavy Breather.

“The biggest difference between Stegoceras and us (in terms of breathing) is that it would have breathed more like a bird or reptile in that it took longer, deeper breaths,” says Ohio University doctoral student Jason Bourke. When Bourke and his colleagues performed a CT scan of a Stegoceras skull last year, they sniffed out some amazing new facts about the way this dino breathed. For example, each breath likely helped keep its brain from overheating by cooling cranial blood vessels. Also, because reptiles lack nose hairs, Stegoceras must have relied heavily on mucous to avoid inhaling small, airborne objects.

5. Stegoceras had Decent Vision.

Both of Stegoceras’ eyes faced forward—which means this dino had depth perception. Not all were so lucky: Many primitive species had eyes that were oriented in slightly different directions. Though this let them take in more scenery, these guys would have struggled with discerning distances. 

6. Four Distinct “Zones” of Bone Were Present Inside its Dome.

As paleontologist Eric Snivley points out, one can see “alternating layers of stiff and compliant bone in the domes of these dinosaurs … It’s almost as if they are wearing a double motorcycle helmet.” For reasons we’re still figuring out, spongy skull material rested beneath a solid outer surface.

7. Its Range Stretched from Alberta to New Mexico.

Next time you’re in Edmonton, check out the University of Alberta’s excellent Stegoceras display. Two mounted specimens can also be seen at the Royal Tyrell Museum (located about 85 miles northeast of Calgary).

8. Stegoceras and A Famous Carnivore Were Briefly Mistaken For the Exact Same Critter.

Hey, hindsight is 20/20. Scientists now know that Troodon was a nimble, sickle-clawed predator, as evidenced by multiple skeletons. For many years, however, we had nothing but its isolated teeth to work with. In the early 20th century, a handful of these pearly whites were found near an assortment of partial Stegoceras skull remains. So, naturally, some paleontologists assumed that they all belonged to a weird, thick-headed chimera-saurus rather than two separate dinos.

9. Stegoceras Had an “S” or “U”-Shaped Neck

Older paintings of Stegoceras (and its relatives) show the animal keeping its neck perfectly straightened and parallel with the ground, ready to ram into whatever might be stupid enough to mess with it. But in life, the creature’s neck was habitually curved [PDF].

10. By Some Accounts, It Could Have “Out-Butted” A Modern Bighorn Sheep.

After scanning the skulls of Stegoceras, a similar dinosaur named Prenocephale, and 10 still-living hoofed mammals, an international paleontology team concluded that these dinos may have been even better at butting heads than today’s bighorn sheep or musk ox. Their research indicates that Stegoceras’ skull was great at dissipating impact forces caused by collisions with solid objects.

This doesn’t necessarily prove that these guys went on head-to-head ramming sessions. Some experts believe that Stegoceras preferred “flanking” each other by swinging those bowling ball-like heads into their rivals’ sides. Frankly, both techniques sound painful—be glad you’ll never have to worry about incurring the wrath of a belligerent Stegoceras.