Book 5, Question 26
Bone to Stone! Why Does a Bone Turn Into a Fossil?
When an animal's bones get buried quickly, water with minerals can slowly seep into them. Over a very long time, the minerals fill and harden the bone until it becomes rock-like. That is how a bone can turn into a fossil that lasts for millions of years.
From the book
Page from A Million Whys Book 5
More fun facts
- Most living things leave no trace after they die.
- Water with no oxygen at the bottom of some ancient lakes kept scavengers away, which helped bodies last long enough to fossilize.
- Water seeps through the rock, and minerals in it can replace bone, shell or other tissue.
- Minerals can also fill the tiny spaces inside bones. Scientists call this permineralization.
- The result is a stone copy of the original bone.
- Over millions of years, the rock can rise to the surface and wear away, uncovering the fossil.
Sources: Science News Explores, National Park Service, BBC
Questions kids ask
Is a fossil bone still made of bone?
Usually not much of it. Minerals have filled or replaced the bone, turning it into a rock copy.