Dinosaurs were one of the first animals to roam the Earth. We are always learning more about them.
1. When did they live?
Dinosaurs first appeared in what is known as the Triassic period, 231.4 million years ago. Different species of dinosaurs lived at different times. There was some type of dinosaur alive until 66 million years ago. The dinosaurs went extinct during the Cretaceous period. That means there were dinosaurs on Earth for 150 million years.
2. How many species of dinosaurs were there?
No one knows exactly how many different kinds of dinosaurs there were. So far we have found at least 500 different types of dinosaurs. We are still finding dinosaurs, and scientists think we will discover many more.
Because there were many different types of dinosaurs, their diets varied. Some were herbivores- they only ate plants. Others, the predators such as t-rex, were carnivores. Carnivores eat meat, and the dinosaur carnivores ate other dinosaurs. Most of the dinosaurs were herbivores.
4. Most of what we learn about dinosaurs comes from fossils.
Dinosaur fossils are the bones of dinosaurs that have been preserved and have gotten buried. We dig them up and place the skeletons back together to learn about the size and body type of the dinosaur. Fossils can also tell us when the dinosaur lived, where it lived, and the food it ate, as well as many other things. Most of what we know about dinosaurs came from the discovery of their fossils.
5. Dinosaurs lived everywhere
Fossils of dinosaurs have been discovered on every continent. That means that dinosaurs lived all over the world. At first the dinosaurs were on Pangaea, which was when all the continents were 1 big land form. Over the course of the time dinosaurs ruled, the continents drifted apart, spreading the dinosaurs all over the Earth.
Most people think dinosaurs were huge. Some were very large- the largest knows so far was 39 feet tall and 74 feet long. However, many were human sized or smaller. Some were even the size of a modern day chicken.
The dinosaurs as a whole were not very smart. Of course, some were smarter than others. Scientists have guessed at the smartest and stupidest dinosaurs based on the size of their brains compared to the size of their body over all. The smartest dinosaur (they think) is the Troodon, being about as smart as a modern opossum. The stegosaurus is believed to be the stupidest.
Dinosaurs laid eggs, and did not give birth. Most of them made nests, like birds do today, although they would typically be on the ground and made out of dirt and rocks. Dinosaurs all cared for their young after the eggs hatched, until the babies were mature enough to fend for themselves.
The dinosaurs went extinct 66 million years ago. This means there are no longer any living dinosaurs. Scientists believe they went extinct when a very large asteroid or comet hit the Earth.
10. Modern day dinosaurs
Many birds evolved from dinosaurs and lived through the extinction. The closest living relative to dinosaurs is still birds.
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