Sharks have inhabited the world’s waters for 400 million years. A remarkable thought, given the fine preservation of their teeth in fossil form to this day. For these impressive remnants of pre-history we have to thank sandy sediment, which covered the teeth after the death of the shark, thereby preventing oxygen and destructive bacteria from reaching them. The fossilisation process then took place over a course of 10,000 years, as minerals in the sediment gradually replaced each tooth’s original dentine and enamel.
Fossilised teeth form the vast majority of shark fossils found. This is largely due to two reasons; firstly, their teeth are formed from dentine, which is a substance harder than bone. The strength of the material allows the tooth to fossilise. Secondly, sharks produce vast amounts of teeth over their lifetime, continuously producing as they lose. Over a lifetime, a shark could produce between 20,000 – 40,000 teeth.