Sciency Words: Dinosaur (An A to Z Challenge Post)

Programming note: If you’re here for today’s Insecure Writer’s Support Group post, please click here.

Today’s post is a special A to Z Challenge edition of Sciency Words, an ongoing series here on Planet Pailly where we take a look at some interesting science or science related term so we can all expand our scientific vocabularies together. In today’s post, D is for:


When I was a kid, dimetrodon was my favorite dinosaur. It has a sail on its back. How cool is that?

Then I found out that dimetrodon is not a dinosaur. It’s just a lizard. Then I found out from this video that it’s not even a lizard.

Also, pterodactyls aren’t dinosaurs. Neither are plesiosaurs or ichthyosaurs. None of my favorite dinosaurs were actually dinosaurs! Frustrating, isn’t it?

So today, I thought I’d give you a quick tip on how to tell when a “dinosaur” is actually not a dinosaur. Sciency Words is all about defining scientific terms, and paleontologists use several key features to define what is or isn’t a dinosaur. For example: the number of openings in the skull, the shape of the hip bone, the type of joint at the ankle….

If you’re a professional dinosaur scientist, you need to know this stuff. But for the rest of us, the easiest way to tell (in my opinion) is by looking at the orientation of the legs. Dinosaur legs are vertical to the ground, not horizontal. They go straight up and down, rather than being splayed out to the sides.

So if you think it’s a dinosaur, but the legs are splayed apart, it’s not a dinosaur.

If you’ve ever seen a crocodile or salamander try to run, you can understand why having your legs splayed apart like that is a disadvantage.

Standing upright on their vertical legs, dinosaurs had a much easier time walking and running on land. Also, vertical legs can support more weight, allowing dinosaurs to become much bigger and much heavier than their cousins, the amphibians, reptiles, and whatever the heck dimetrodons were.

Next time on Sciency Words: A to Z Challenge, we’ll find out what our planet’s name is.

13 thoughts on “Sciency Words: Dinosaur (An A to Z Challenge Post)

    1. I hadn’t thought about it that way. Actually, I’ve read that the dinosaurs may have grown too big for their own good, and that even without the K-T asteroid, they probably would have gone extinct anyway because the ecosystem couldn’t support them for much longer. Maybe being a smaller, less complex organism has its advantages too.


  1. I think a big part of the confusion comes from the fact that dinosaurs have historically been depicted as lizard-like. But from what I understand, they were far more bird-like, including in many cases having feathers, or perhaps proto-feathers in the earlier species.

    Liked by 1 person

    1. It’s incredible how those old depictions of dinosaurs have endured in the mind of popular culture. Most people do seem to be aware of the thing about feathers, or at least they seem to have heard something about it. And yet I rarely if ever see a feathered dinosaur toy or feathered dinosaur art (aside from illustrations in Scientific America or similar publications).

      Liked by 1 person

    1. I think I first heard about the leg thing at an art seminar. We had a lecturer talking about doing scientific illustrations, such as illustrations of extinct animals. Wherever I first heard about it, my immediate reaction was, “Oh! That’s so easy!”


  2. Hey, that info on dinosaur legs was great. I never noticed that before. Thanks. I’ll have to find a way to work that into a conversation with my kids sometime in the near future. They’ll either be impressed or ignore me.

    Liked by 1 person

Leave a Reply

Fill in your details below or click an icon to log in: Logo

You are commenting using your account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s

This site uses Akismet to reduce spam. Learn how your comment data is processed.