Sharks are ancient and successful predators, having survived for over 400 million years. Their survival is closely linked to their specialized dental structure. Unlike most vertebrates, a shark’s survival depends on a perpetual supply of sharp, functional teeth to secure and consume prey. This continuous dental regeneration is a reason why their teeth are often found fossilized.
The Rows and Total Count
The number of teeth a shark has at any given time is not fixed, but rather a dynamic range. Most sharks possess between 50 and 300 teeth simultaneously, arranged in multiple layers within their jaw. This unique structure is a form of polyphyodonty.
A typical shark jaw holds five to seven rows of teeth, though some species may have up to ten or more. Only the first one or two rows are actively used for biting or cutting prey; these are the functional set. The rows behind them are successional teeth, waiting to rotate forward.
A Great White Shark, for instance, may have around 300 teeth in its jaw at once, but only a fraction are exposed and active. The total count varies significantly by species; a Bull Shark can have over 350 teeth in its mouth at one time.
The Constant Tooth Replacement Cycle
The biological mechanism driving this high tooth count is continuous and rapid replacement, operating like a natural conveyor belt. New teeth constantly develop in the soft tissue lining the inner jaw, on a structure called the dental lamina. These replacement teeth slowly move forward, pushing the older, functional teeth out and replacing them seamlessly.
The rate of replacement is highly variable, influenced by the shark’s diet, age, and surrounding water temperature. In warmer waters, the metabolic rate increases, and teeth can be replaced much faster. Some smaller, active species, like the Lemon Shark, may replace a tooth row in as quickly as eight to ten days. Other species, such as the slower-moving Catshark, may take up to five weeks or more.
Since the teeth are not rooted in the jawbone but are embedded in soft tissue, they are easily shed when worn down or broken during feeding. Sharks do not develop cavities because damaged teeth are simply discarded and replaced before significant wear occurs. Over a lifetime, some Carcharhiniformes can cycle through 30,000 to 35,000 teeth, while a Great White Shark may lose up to 50,000 teeth.
Specialized Teeth Across Species
The shape and size of a shark’s teeth are adapted to its specific role in the marine ecosystem and the type of prey it hunts. For instance, the teeth of the Great White Shark are broad, triangular, and heavily serrated, designed to saw through the tough flesh and bone of large marine mammals.
In contrast, the Shortfin Mako Shark, which preys on fast-moving fish, has slender, needle-like teeth that lack serrations. These teeth pierce and grip the bodies of quick prey, preventing escape.
Bottom-dwelling sharks, like the Nurse Shark or the Port Jackson Shark, have a completely different dental structure. Their jaws are lined with dense, flattened, pavement-like teeth that are ideal for crushing the hard shells of mollusks and crustaceans.
The Tiger Shark exhibits a curved, broad tooth with distinct serrations, allowing it to act like a can-opener. This unique shape is adapted to cut through tough materials, including the shells of sea turtles, which are a common part of their diet.