What Is a Dinosaur?

What exactly is a dinosaur? Contrary to popular belief, dinosaurs are land-dwelling reptiles with one of two hip structures that place their legs directly underneath them. Depending on the type of hip structure they have, dinosaurs are broken up into two groups called orders. These orders are Saurischia (which comes from the Greek root for lizard, saur- and hip, ischia) and Ornithischia (again, ornith- Greek for bird, and ischia, Greek for hip). Each order has multiple suborders. For example, the saurischians include the subgroups Theropoda and Sauropodomorpha, while the ornithischians include the subgroups Thyreophora, Ornithopoda, and Marginocephalia. Scientists use these groupings to better understand similarities in animals, and some believe that means they evolved from a common ancestor.

Photo taken at the Creation Museum
Dinosaurs and Humans

So what does the Bible say about this? Being land animals, they were created on day six of the creation week. Therefore, flying reptiles (like Pteranodons and other pterosaurs) and marine reptiles (such as mosasaurs or plesiosaurs) cannot be classified as dinosaurs because both were created on day five of the creation week. Pelycosaurs, such as Dimetrodon (an animal often grouped with dinosaurs), are not dinosaurs either because they walk with their legs sprawled out to the side like a lizard rather than directly beneath them. And finally, crocodilians, such as Sarcosuchus or Deinosuchus, are not dinosaurs because of the way they walk.

Did you know that the Bible likely mentions dinosaurs? Though the word dinosaur didn’t exist when the Bible was translated into English, the word dragon did. Dragons are mentioned multiple times throughout Scripture, and many believe that the dragons mentioned may be describing now-extinct reptiles (including dinosaurs!).

The earliest discovered dinosaur fossils were often called dragon bones by early paleontologists because the word dinosaur didn’t exist yet. It was coined in 1841 by Sir Richard Owen, a Christian anatomist of the day. It best translates as “fearfully great lizard,” though “terrible lizard” is what we see most in modern translations.

Do you know what the very first dinosaur ever discovered was? The Megalosaurus, which means “great lizard,” is often considered the first dinosaur ever discovered in modern times. It was originally named by William Buckland in 1824, but some reports say it was discovered as early as 1676!

October is “dinosaur month!” Every weekday of this month, you can come back to our Kids site to read about my 20 favorite dinosaurs. I hope you’ll join me!