Shark Teeth
Tiger Shark Teeth © Wikimedia Commons, Stefan Kuhn.

Sharks have to fend for themselves immediately after birth and so are born fully equipped with their own teeth. Made of enamel, their teeth are strong and hard and therefore appear in huge numbers in the fossil record - it is possible to find unspoilt razor-sharp teeth that are hundreds of millions of years old in sedimentary rocks, rivers and seabeds.

The teeth of a shark are larger versions of the denticles that cover their body. Behind the front row of teeth, multiple new rows are formed in the mouth. As the front rows wear down or fall out, a new row will move forward from the back of the jaw to replace them, similar to a conveyor belt, ensuring that the shark continually has a full set of teeth. These replacements happen approximately every two weeks and depending on the lifespan of the shark, some can lose 30,000 teeth in their lifetime!

Different sharks have different shaped teeth depending on their food preference. Sharks that eat shellfish and crabs have flat crushing teeth. Sharks that eat fish have pointed teeth suitable for gripping and those that eat much larger prey (such as seals and other mammals) have sharp, serrated cutting teeth. The shapes of the teeth vary depending on their position in the jaw and also may change with the age of the shark. Younger/smaller sharks may start out with smaller spear–like teeth, perfect for catching small fish, and then as they get older become flatter to accommodate larger prey.

Filter feeding sharks – Megamouth Shark, Basking Shark and Whale Shark – still have tiny teeth however these are not used for feeding. Each species has hundreds of tiny teeth running along the gumline of both the upper and lower jaws, these teeth are only 5-6mm long and hook-shaped. Some researchers believe them to be vestigial and so will eventually disappear over time, whereas others believe that they may be used during fin-biting as part of mating.

Basking Shark Teeth © Marc Dando.
Basking Shark
Smallspotted Catshark Shark Tooth © Marc Dando.
Smallspotted Catshark
Spiny Dogfish Tooth © Marc Dando.
Spiny Dogfish
White Shark Tooth © Marc Dando.
White Shark

Shark teeth and jaws often enter into the curios trade, being sold as souvenirs and as jewellery. In the past, teeth have been used to make weapons and tools.


Related Links:

Skeleton

Skin

Fins

Gills

Neutral Buoyancy

Muscles

Temperature Control