"Skulls are often associated with death, but like all bones, they are composed of living tissue. Constantly changing, they grow larger, stronger or weaker depending on age, diet and exercise. They can also heal themselves when broken. Because of this, a skull is like a good book - it can record the major events and traumas in an animal's life. Scientists read skulls to determine how long individuals lived, how healthy they were, and how they died. "