Fossils are what’s left of plants or animals after being buried in mud for a very long time until it turns into rock. Hard parts of animals, like bones and teeth, are the most common things that turn into fossils. Fossils can also be in the shape of something that has been left behind by an animal, like a footprint or a burrow – a hole that an animal dug in the ground to live in.
Some fossils are the remains of animals that lived long ago and are now extinct, like dinosaurs. Although there are no dinosaurs alive now, we know they existed because of fossils that have been found all over the world. There are many different kinds of fossils, and the scientists that study them are called paleontologists (PAY-lee-un-TAL-uh-jests).
A fossil is formed in the same shape as the hard part of the animal, like a tooth or bone. The soft parts of plants or animals, such as the scales of a fish or the leaves of a plant, sometimes leave a little bit of color in the rock before they eventually break down into nothing. Soft things that turn into fossils usually leave an imprint of their shape as they slowly break down, so it is pressed into the rock instead of being raised up like fossils from hard things are.
Dinosaurs are animals that lived a long time ago. They are extinct now, which means that as far as we know, all of them have died. Dinosaurs were reptiles, like lizards and turtles. However, most dinosaurs were very large, the biggest ones were bigger than the largest reptiles that are alive today. Most dinosaurs hatched from eggs.
There are lots of pictures of dinosaurs and even complete dinosaur skeletons on display in museums. Since dinosaurs are extinct, no one has ever seen a living one. That means the pictures you see of dinosaurs are just guesses at what dinosaurs look like. When fossilized dinosaur bones are discovered, they have to be put together like a puzzle.