We know most of our information about dinosaurs from the bones and fossils that paleontologists have found in the ground. These bones have told us about what dinosaurs looked like, the ways they were built, and even the ways their bodies worked! There are also other fossils that paleontologists have found from the same time period.
Some of these fossils belonged to saber-toothed tigers, some belonged to mammoths, and some even belonged to other reptiles that were similar to dinosaurs…but were altogether different! Not all fossil animals are dinosaurs, but all the things we know about dinosaurs have come from fossil animals.