Sharks, ancient predators of the ocean, possess a unique and efficient dental system. This system allows them to maintain a continuous supply of sharp teeth throughout their lives, an advantage in their marine environment.
The Remarkable Shark Dentition
Sharks feature multiple rows of teeth, a distinct departure from the single set found in most mammals. The exact number varies by species, but many sharks have between 5 and 15 rows in each jaw. Some species, like the bull shark, can even exhibit up to 50 rows. The outermost rows are the functional teeth used for biting and grasping prey. Rows behind these serve as replacements, continuously developing and moving forward, ensuring sharks always have a sharp and effective biting surface.
A Continuous Supply of New Teeth
Multiple tooth rows are linked to a shark’s continuous tooth replacement system, often likened to a “conveyor belt.” Unlike humans who have a limited number of tooth sets, sharks constantly shed and regrow teeth. When a front tooth is lost or damaged, the tooth behind it moves forward. This replacement can be rapid, with some sharks replacing a tooth in as little as 24 hours, though it can take several days or months. This constant turnover means a single shark can shed tens of thousands of teeth over its lifetime, ensuring its feeding apparatus remains effective, a system possible because shark teeth are embedded in the gums, not directly affixed to the jawbone, allowing for easy detachment and forward movement.
Diversity in Dental Design
While multiple tooth rows and continuous replacement are general shark characteristics, the number of rows and tooth shape vary considerably among different shark species. These variations are directly related to a shark’s diet and hunting methods. For instance, fish-eating sharks often have needle-like teeth for gripping slippery prey, while those consuming mollusks and crustaceans possess dense, flattened teeth for crushing hard shells. Predators of larger prey, such as the great white shark, feature pointed lower teeth for gripping and triangular upper teeth with serrated edges for cutting flesh. Even filter-feeding sharks, like the whale shark and basking shark, have numerous tiny, non-functional teeth, despite not using them for chewing. This diversity shows how dental design is a specialized adaptation, allowing each shark species to thrive within its ecological niche.