Renee Tikena, of Tikipunga Primary School, asks :-

How long could a dinosaur live?

Michael Eagle, a geologist at Auckland Museum, responded.

We do not know exactly just how long a dinosaur could live. However we can make a guess by looking at their teeth and bones. The shape and size of their teeth tell us what dinosaurs may have feed on. How well the teeth are worn can help us estimate how long the reptile had been using them.

Most living reptiles have very slow-growing bone. If you were to look at a piece of bone taken from a reptile such as a lizard, it would look like solid cow bone and be made of rings. For each year of life there is one ring, just the same as the growth rings in trees. Bone growth was very rapid in some baby dinosaurs and not so in others. Some dinosaurs, particularly when food was plentiful, grew quicker than others. As long as there was plenty of food and the weather was kind to them, dinosaurs lived quite a long time. Using these methods scientists have worked out that the dinosaur Tyrannosaurus rex, for example, lived for about 25 to 35 years in good times.