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What was a Stegosaurus? - Facts for Kids

Updated: Jun 14, 2023

Welcome to the third article in Imagining History's Dinosaur Guide. In our previous entries we learnt that the three horned Triceratops, weirdly, only had two proper horns and one pretend one. We also discovered that the T-Rex was probably feathered and would definitely beat you in an arm wrestling contest. In this article, we're taking a looksie at the world famous Stegosaurus. Let's get right to it and learn some stuff!

Courtesy DinoTeam

When did Stegosaurus live? Am I likely to find one hanging around at the bus stop?

Not likely, sadly. Stegosaurus - like all dinosaurs - is long extinct. Stegosaurus lived in the late Jurassic period, around 150 - 155 million years ago. That means that a Stegosaurus would never have met a T-Rex or a Triceratops, but it may well have stopped for a natter with a Diplodocus.

Did Stegosaurus eat plants?

You guessed it, they were herbivores and would likely have chewed on plants like cycads, ferns and horsetails. By the way, horsetails are not the tail of a horse (confusing, I know). Instead it is a plant that looks a bit like green bamboo.

Courtesy Prehistoric Kingdom Wiki

What does the word 'Stegosaurus' even mean? It's a very weird word.

You're right, it is a weird word and the meaning of it is even weirder. Stegosaurus means 'roof lizard'. This isn't to suggest you should get your mum to ring Stegosaurus and Sons if she wants the hole in her roof fixed. After all, dinosaurs have no opposable thumbs and so would not be able to grip a hammer.

Instead, the 'roof' in 'roof lizard' describes the protective plates running along the creature's back.

Who was responsible for this silly name?

That would be the American palaeontologist Othniel C. Marsh, the person who first discovered Stegosaurus way back in 1877. He believed the triangular-like plates that were attached on top of the Stegosaurus' back acted like armour plating. So, he went with the whole 'roof lizard' thing.

Though, fun fact, Othniel actually thought he'd discovered the remains of a giant prehistoric turtle before realising his mistake.

Courtesy Christophe Hendrickx

How many of these plates were there?

There were between 17 and 22 of these plates on each Stegasaurus. Each plate - called a 'scutt' - was around 60 centimetres tall and 60 centimetres wide. They weren't made of bone though and they weren't attached to the Stegosaurus' back bone - as Othniel C. Marsh believed. Instead they were more like hardened skin that grew over time - a bit like the thick scales of a crocodile.

What were these plates for?

One glance at those deadly looking plates and it's easy to think they were for self defence. That's only one theory though. Other theories suggest the plates were used to regulate Stegy's temperature. The plates would absorb light during the day to heat the Dino's body during a cold night.

Courtesy Tim Evanson

Some believe that the plates were used to impress other dinosaurs - a bit like the extravagant feathers of a peacock. Then there are a bunch of palaeontologists who had the bright idea that the plates could change colour to communicate to other members of the herd.

Finally - phew - there's a theory that the plates just made the Stegosaurus look really big and imposing. This would help scare off any predators who fancied a quick nibble.

What about the tail then, surely that was used for defence?

Absolutely. Stegosaurus was a big 'un. Weighing between 5 to 7 tons (that's the same weight as three rhinos or, if you prefer, two whale tongues) and at 29 feet in length (about the same length as a London bus) it's safe to say that if a Stegosaurus hit you with its tail it would really hurt. Also, there were spikes on a Stegy's tail, each one was three feet long and very sharp, so it wouldn't just really hurt - it would really really hurt.

Courtesy Scott A. Hartman, GetAwayTrike

Bonus fact - the Stegosaurus' tail is called a 'Thagomizer'. Surely the best name for anything, ever?


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