Hypsilophodon was discovered all the way back in 1849, and our outlook on this little animal has changed quite a bit since then.

1. Scientists Used to Think that Hypsilophodon was an Avid Tree-Climber.

When Victorian paleontologists started looking over the creature, many mistakenly assumed that one toe on each foot opposed the others. As anyone who’s ever buttoned a shirt can attest, grasping things gets a lot easier when you’ve got opposable digits to work with. So Hypsilophodon was painted as a reptilian tree-fancier, scurrying up the nearest trunk for safety whenever predators came around.  

But, as later research would reveal, Hypsilophodon’s toes weren’t oriented that way at all. Instead of scaling timber, this dinosaur was clearly built for high-speed sprints on solid ground.

2. Specialized Bones Shaded its Eyes.

Thin, pointy palpebral bones jetted out over the top half of its eyes, forming bars that functioned like a baseball cap’s bill—and gave it a fierce, hawk-like look to boot.

3. Hypsilophodon is Known Exclusively From an Island off the Coast of England.

Bits and pieces of almost 100 individuals have been recovered on the Isle of Wight. They’ve got plenty of company: Over 20 different dinosaur species once lived there. 

4. Hypsilophodon Most Likely Had Dino-Cheeks.

Cheeks aren’t just for pinches—they’re also a great way to keep food from falling out of your mouth. Not all dinosaurs bothered with chewing, but Hypsilophodon’s teeth sliced up its meals to some extent before the animal swallowed. Given this fact and the shape of its skull and jaws, there’s ample reason to conclude that Hypsilophodon had cheek-like structures.

5. An Entire Herd Might Have Been Ensnared by Quicksand.

Scientists have found a ton of Hypsilophodon bones in one area on the southwestern coast of the Isle of Wight. Here, several animals died in close proximity, and because the surrounding sediment shows traces of water-logging, it's likely the remains belonged to a Hypsilophodon herd that died together via quicksand.

6. Originally, This Herbivore Was Mistaken for a Juvenile Iguanodon.

Sir Richard Owen—who, incidentally, coined the word “dinosaur”—thought Hypsilophodon represented nothing more than the sub-adult version of a very different dinosaur. Iguanodon was a hefty, thumb-spiked plant-eater which is, in fact, only distantly related to the smaller animal.

7. Seeds Might Have been One of Hypsilophodon’s Favorite Foods.

In its heyday 125 million years ago, cycads—cone-like seed plants—were wildly successful. A paper released in 2010 argued that Hypsilophodon's beak would have been well-equipped for yanking seeds from cycad cones, and that its front teeth could hypothetically strip away their protective outer layers so the broader back teeth could mash the seeds up.

8. Contrary to What You Might See in Older Paintings, Hypsilophodon Lacked Body Armor.

In 1874, surgeon and amateur paleontologist John Hulke found what he believed to be bony blobs of armor-plating on the backs of a few Hypsilophodon skeletons. Further inspection has proven that what he’d actually been looking at were plates of cartilaginous tissue situated between its ribs. On a live animal, this material would have have been submerged under the skin and of little to no defensive value.

9. Hypsilophodon’s Ribs Could Handle Strenuous Workouts.

What exactly was that tissue for, anyway? According to Dr. Richard Butler of the University of Birmingham, “the plates might have functioned to support the ribcage during fast running.” If true, the tissue would have prevented Hypsilophodon’s ribs from colliding and, probably, given its lungs more breathing room (literally) whenever the dinosaur felt a need for speed.

10. It Was Discovered by a Fossil-Loving Reverend.

William Fox (1813-1881) had a passion for digging dinosaurs that rivaled his love of ministry. According to his own wife, it was “always bones first and the parish next” for the clergyman. Fox fell in love with Wight and its treasures, writing, “I cannot leave this place while I have any money left to live on, I take such deep [joy] in hunting for old dragons.” Later on, two of the “dragons” that the dedicated amateur brought to light would be named in his honor, namely the spike-covered Polacanthus foxii and speedy Hypsilophodon foxii