Teeth from more recent fossils reveal more because they have more isotopes preserved in them. For example, the nitrogen in the teeth of Neanderthals can reveal whether the protein they ate came from plants or animals.
An animal's teeth is literally shaped by its food. That's according to new research from the Department of Geology at the University of Leicester, published in the Royal Society journal Interface. Research shows that the roughness of tooth surfaces can reveal what an animal has been eating.