Sharks’ teeth are essential for their survival and a subject of widespread fascination. These dental structures reflect millions of years of evolutionary adaptation for an aquatic hunting lifestyle.
The Great Number of Shark Teeth
Sharks possess a remarkable number of teeth, with an average individual having between 50 and 300 at any given time. Unlike human teeth, they are embedded in gum tissue, not jawbone. This allows for multiple rows of teeth, typically 5 to 15, though some species like the bull shark can have up to 50 rows in seven series.
Only the outermost row of teeth is actively used for feeding, while rows behind are constantly developing and ready to move into position. The number and arrangement of teeth vary by species, reflecting their diverse diets. For instance, a great white shark may have approximately 300 teeth total, with around 50 active teeth supported by five to six developing rows. These teeth are large, flat, triangular, and serrated, designed for cutting large prey.
Nurse sharks have 58 to 76 tiny, serrated teeth specialized for crushing hard-shelled crustaceans and mollusks. Filter-feeding sharks, such as whale sharks and basking sharks, have greatly reduced, non-functional teeth. The frilled shark, a deep-sea species, can have as many as 300 backward-curved teeth.
The Science Behind Shark Teeth
The abundance of shark teeth is attributed to a continuous “conveyor belt” replacement system. New teeth continuously develop from specialized dental lamina tissue. As front teeth are lost or worn down, new ones from the rows behind gradually move forward and rotate into place. This rapid turnover ensures sharks consistently maintain a sharp and effective set of teeth.
Sharks shed teeth throughout their lives, some losing at least one per week. For certain species, a lost tooth can be replaced in as little as 24 hours. This high rate means a single shark can go through 25,000 to 35,000 teeth over its lifespan, with great white sharks replacing up to 50,000.
Shark teeth consist of an inner core of dentine and an outer enameloid layer. Enameloid is hard due to fluoroapatite, a resistant calcium phosphate mineral. This composition contributes to their teeth’s durability. The continuous renewal allows sharks to remain effective predators.
The shape of a shark’s teeth is closely adapted to its diet. Great whites, preying on large marine mammals and fish, have sharp, serrated teeth for tearing flesh. Bull sharks, consuming slippery fish, often have needle-like teeth for gripping. Bottom-dwelling sharks, like nurse sharks, feeding on hard-shelled organisms, feature dense, flattened teeth for crushing.