What is a dinosaur?

A very good question. I'm glad I asked it. Well, the simple answer is, they're animals just like you, me and Fido, and Kitty and the birds in trees. Although, you and I as well as the family dog or cat are mammals, dinosaurs are their own group: dinosauria.

Their closest relatives are crocodiles (and alligators) and birds. Yeah, don't see the family resemblance, do you? Well, there are many criteria that scientists go through and analyze before they classify an animal. A lot of it is down to similarities in bones, like the hip, skull, ankle, or wrist. It's basically a method called comparative anatomy. Scientists will compare newly found bones with previously discovered ones. This is why sometimes a bone is discovered, but the animal is not classified until much later when a more complete specimen of the animal is discovered.

Scientists will look at teeth, claws and the way a dinosaur is built to determine if it was a carnivore (meat-eater) or herbivore (plant-eater). That's why it is so important to find as much of the specimen as possible. The more parts you have to work with, the easier it will be to figure out what exactly it is you've found. If you're lucky enough to find a hip, leg, or certain parts of a skull, you might even be able to estimate the size of a dinosaur without actually finding the whole thing.

Ultimately, dinosaurs fall into two groups: Ornithischia (bird-hipped) and Saurischia (lizard-hipped). These classifications are based on the shape of the hip bone and pelvis area. Ornithischia have hips that are shaped like that of birds. And Saurischia have hips shaped like a lizard or reptile. All ornithischians are herbivores, but saurischians can be carnivores and herbivores. Oddly, the dinosaurs that are supposed to be the closest relative of birds, are the lizard-hipped ones. Go figure!

So, now you know what a dinosaur is. That wasn't hard, was it? Another wrinkle on the brain. Basically dinosaurs are just animals. They are real. They are not made up monsters from someone's fertile imagination, although some may look like it. Although portrayed as monsters in movies most of the time, they would act just as a lion, hippo, elephant or any other animal would today. Basically, they would just do what they do.

Next-Classification.