By Blaise Jones
The teeth of all sharks are enlarged versions of their dermal denticles, which coat their skin. The teeth are made of dentine, covered by enamel, and at the center lies a pulp cavity filled with blood and nerves. However, while all sharks’ teeth are made of the same substance, they do not share the same shapes.
Tools of the Trade
Just as the size and shape of a shark varies depending upon the species, so, too, do their teeth. Many sharks are specialist hunters, meaning that they focus primarily on one (or just a few) type of prey animal(s). Over time these specialist predators have developed specialized tools to help them hunt. None so more specialized than their teeth.
There are four major types of shark tooth, and each of these types have their own subsets. The four major groups of shark teeth are: narrow and needle-like, broad and serrated, thick and plate-like, and small and peripheral.
Let’s Narrow it Down
Sharks that have the narrow needle-teeth focus more on hunting small fish and squid. These sharks rarely ever try to eat anything bigger than their mouths because their teeth are ill-suited for ripping or tearing. Instead, these teeth serve like fish hooks, piercing their prey and gripping them tightly. A prime example to these kinds of teeth can be seen in the sand tiger shark, which you can find in almost any aquarium.
Broad, serrated teeth are found in many of the larger species of shark, such as the great white shark and tiger shark. Theses teeth are adept at ripping and tearing, and are used to cause the most damaged possible to the prey item. This is because sharks with these kinds of teeth hunt larger animals, and thus have to inflict deadly wounds as quickly as possible so their prey cannot escape and they lose a meal. The serrations on their teeth allow these sharks to saw chunks of meat from their prey. This lets them cut off bite-sized morsels of larger animals.
You can see sub-specialization among this group of teeth, most obvious when you look at the tooth of the tiger shark. Tiger shark teeth have an odd, curved shape to them and are often compared to can openers. Tiger sharks live in low-production environments, leading them to be voracious scavengers. Their tooth shape has allowed them to more easily prey on one of the more abundant animals in their environments: sea turtles.
Sharks that have the crushing plate teeth are bottom feeders. These are the sharks that live on the bottom and prey upon hard-shelled animals like mollusks and crustaceans. These sharks rarely have large numbers of teeth, instead having a few very large slab-like teeth. Sharks which have these types of teeth include the shark ray and the smooth hound shark.
On the Way Out
The final group of teeth are the small and unused teeth. These are the teeth found on whale sharks, basking sharks, and other filter feeding species. These sharks feed primarily off of microorganisms, such as zooplankton and krill, filtering through their gills. The gills are coated in ridges called gill rakers, which sieve the microorganisms from the water. The teeth aren’t used at all when feeding and are receding. It’s quite possible that one day they will disappear entirely.
“The Encyclopedia of Sharks: by Steve Parker