None of the fossil skeletons contain any real bone. All the organic material that was once there had already decomposed millions of years ago. What we are looking at in the museums are technically just stones. When an animal dies, most of the body decomposes quickly, leaving skeletal remains. A fossilized skeleton occurs when the skeleton gets covered in sediment. The sediment hardens into stone to preserve the remains.
The fossilization process slowly replaces organic material like bone with inorganic minerals that are present in water. This way, the remains can stay preserved long enough for human beings to see them. Sadly, the remains of most animals, including dinosaurs, usually dissolve completely, leaving no record behind. Only a small fraction of the millions of dinosaurs that used to exist have managed to leave behind fossilized skeletons.
Read more about how fossils are made!
19 Totally Mind-Blowing Facts