Sharks possess a remarkable characteristic with their teeth: a continuous cycle of growth and replacement. Unlike most creatures with a fixed set of teeth, sharks have a unique dental system. This ensures they always have sharp, effective tools for their predatory lifestyle, allowing for a continuous supply of new teeth throughout their lives.
The Constant Supply of Shark Teeth
Sharks do not have a fixed number of teeth like humans; instead, they maintain a continuous supply. They typically have multiple rows of teeth, with numbers varying significantly by species, often ranging from 2-3 to as many as 15 rows in each jaw. For example, a bull shark’s jaws might contain up to 50 rows, while some filter feeders like the basking shark can have over 200 rows of tiny teeth. At any given moment, a shark can have anywhere from 50 to 300 teeth in various stages of development, with a great white shark potentially housing up to 300 active teeth.
Over their lifespan, sharks can shed and replace thousands of teeth. Some species, like the lemon shark, are estimated to lose over 30,000 teeth. Certain ground sharks, including hammerheads and tiger sharks, may go through approximately 35,000 teeth. Estimates suggest a single shark can produce over 50,000 teeth in its lifetime, with great white sharks potentially regenerating up to 200,000 teeth.
The Mechanics of Tooth Replacement
The continuous supply of shark teeth relies on a unique “conveyor belt” system. Unlike human teeth, shark teeth are not deeply rooted in the jawbone; instead, they are embedded in connective tissue or gums. This allows for easy shedding and replacement without complex dental procedures. New teeth constantly develop in rows behind the functional ones, positioned on the inner surface of the jaw.
When a tooth in the outermost, functional row becomes worn, broken, or falls out, the tooth directly behind it moves forward to take its place. This forward rotation ensures the shark always maintains a sharp and effective set of teeth for hunting and feeding. Replacement speed varies by shark species, age, diet, and water temperature. On average, a shark might lose at least one tooth per week, but a new tooth can move into position in as little as 24 hours. Younger sharks replace teeth more frequently, and warmer water temperatures can accelerate this turnover.
Diversity in Shark Dental Anatomy
While all sharks have a constant tooth supply, their teeth’s form and function vary greatly, reflecting diverse diets and hunting strategies. The shape and size of a shark’s teeth adapt to the type of prey it consumes. This dental specialization allows sharks to exploit different ecological niches.
For example, sharks feeding on slippery fish and squid often have long, slender, needle-like teeth, ideal for gripping prey, such as mako and blue sharks. In contrast, species preying on large marine mammals, like the great white shark, have broad, triangular, serrated upper teeth paired with pointed lower teeth. These serrated edges efficiently slice through flesh and bone. Sharks consuming shellfish and crustaceans, such as the nurse shark, exhibit dense, flattened teeth designed for crushing hard shells. Even filter-feeding sharks, like the whale shark and basking shark, possess numerous rows of very small, non-functional teeth, remnants of their evolutionary history.