Did you know that the first dinosaur was born about 230 million years ago? That was a long, long time ago.
How old are you? Think of that number, and take it and stretch it out all the way to the Moon… about a thousand times. That’s how long ago the very first dinosaur was alive.
When dinosaurs were born, the Earth was a very different place. Do you know about the continents? When dinos were around, there was only 1 continent. All of the different places on Earth were part of one big land. So if a Dinosaur wanted to, he could walk from where you live now all the way to Australia… if he had a lot of energy!
Plus, the weather was a lot different. When dinos were first born, Earth was hot and dry… even in places like Antarctica that are now covered in snow. Days were shorter too, because the Earth actually spun around the Sun a little bit faster.
You probably think of dinosaurs as giants, but the first dinos were pretty small. Some of the earliest ones we know about were called Herrerasaurus and Eoraptor.
The Erorapter was about 3 feet tall and weighed around 20 pounds. It was really fast, and would hunt other animals and eat plants.
The Herrerasaurus was bigger. He could grow to be about 20 feet long, and weighed over 700 pounds. The Herrerasaurus was a hunter… so watch out if you ever see one!
As time went on, more and more Dinosaurs were born. Do you know about the theory of evolution? It means that animals, like dinosaurs, will keep changing and turning into new types of dinosaurs as time goes by.
The dinosaurs evolved into two different basic types: the Saurischians, like the Dilophosaurus.
The other types were the Ornithischians, which were the dinosaurs that ate plants, like the Stegosaurus.
Inside those two groups, over 800 types of dinosaurs evolved… that we know about so far. Scientists discover new types of dinosaurs all the time, and sometimes they go back and figure out something new about dinosaurs they already found. So they might change what a dinosaur is called or whether it’s part of another group.
By the way, did you know that scientists who study fossils like dinosaurs are called Paleontologists? Some of the most famous paleontologists were Jack Horner, Mary Anning, and Edwin H. Colbert. And the very first person to find a dinosaur fossil was Reverend Robert Plot, in England. The year was 1640. That was a long time ago!
As time went on, dinosaurs evolved to be pretty amazing!
The Apatosaurus was a type of dinosaur that grew over 75 feet long, weighed about 22 tons, was 15 feet high, and could actually make a sonic boom with his tail. Have you ever heard a sonic boom? Sometimes planes make them when they fly over your head really, really fast.
You’ve heard of the T-Rex, right? Some people call him the King of The Dinosaurs. T-Rex was one of the best hunters of all time… all the other dinosaurs ran when they saw him coming. A T-Rex was about 13 feet tall (taller than your parents!), weighed about 9 tons (almost as much a school bus), and could run almost as fast as a deer!
Some dinosaurs could see in the dark! The Velociraptors were hunters that were about the size of a big turkey. They had long claws and were really fast… in addition to having super night vision powers! Ask your parents if they’ve ever seen any movies with Velociraptors in them.
One dinosaur learned to be a really good swimmer! She was called the Spinosaurus, and she actually had webbed feet, like a duck. She was such a good hunter, she could even catch sharks! A Spinosaurus could get pretty big too: almost 60 feet long, which is bigger than T-rex… and longer than your school bus!
Do you have any toys that look like this guy? His name is Triceratops. He would grow to be about 30 feet long, weighed about 20 tons, had 3 horns on top of his head and ate plants. Triceratops lived in what is now North America, and the first fossil was found in 1889!
So what happened to all the dinosaurs? Well, you probably know that they disappeared a long, long time ago. We call this going “extinct.”
Scientists are still working on figuring out exactly why all the dinosaurs disappeared. Many scientists think that a meteor, which is like a giant rock from outer space, hit the earth so fast that it changed the Earth’s climate. Some scientists think it was because of volcanoes, or that the dinosaurs wound up running out of food. Maybe one day, when you’re older, you can help the scientists figure out this mystery!
You might think that it’s sad that the dinosaurs disappeared. But for a lot of other animals, it was great news! Lots of creatures, like elephants, cats, and dolphins, were able to find new homes with the dinosaurs gone.
And by the way, there is still one kind of dinosaur left, and you probably see them every day. They’re called…
Birds! That’s right, birds are descended from dinosaurs, so technically there are still lots of dinos left on Earth. Good thing chickens aren’t 75 feet long, though!
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