Room 3, of Paroa School, asks :-

How can scientists tell the age at death just from a human skull?

Nancy Tayles, an anatomist at the Otago Medical School, responded.

This is not difficult when the skull is from a child. The best evidence comes from the teeth. The deciduous (baby) teeth start developing before birth and start erupting at about six months. The permanent (adult) teeth start developing at about birth and gradually erupt to replace the deciduous teeth from the age of six. We know the sequence and rate of development, so we can estimate the age by looking at the teeth. The best estimates are made by looking at an x-ray (radiograph) to see the unerupted teeth. If the teeth have not survived, we can make a less precise estimate of age by looking at the size of the skull.

Estimating the age of adults is more difficult but teeth again give the best estimate. As people get older, their teeth are worn down by chewing food so we can look at the amount of tooth wear. This does not occur at the same rate for everyone, because it depends on the type of food the person has eaten and how good their teeth were. Other methods involve changes with age in the joints between the bones of the skull and are even less precise as people age at different rates. Often the best estimate for adults is within a range of 5-20 years.