Shark teeth are dynamic biological structures, perfectly suited for their predatory lifestyles. Unlike human teeth, they are part of a continuous system. Their appearance varies widely, reflecting the diverse feeding habits of these marine animals.
General Characteristics of Shark Teeth
Shark teeth have a hard, mineral-rich outer layer called enameloid, a highly durable tissue. Beneath this exterior is a core of dentine. Unlike human teeth, they are not anchored in sockets but held by connective tissue. Many teeth feature serrations, small saw-like edges, which help them efficiently cut and tear prey. Fluoride in their tooth surface provides natural cavity resistance.
Diverse Forms Across Shark Species
The shape and size of a shark’s teeth relate closely to its diet, showing a broad spectrum of forms. Sharks targeting large, fleshy prey, like Great White and Tiger Sharks, have triangular teeth with serrated edges for tearing and slicing. Great White Sharks have pointed lower teeth and triangular, serrated upper teeth. Tiger Shark teeth are cockscomb-shaped, with serrations that are themselves serrated, enabling them to process tough materials.
Other species, such as Mako and Sand Tiger Sharks, have long, needle-like teeth effective for grasping slippery fish and squid. Mako shark teeth curve inward, designed to pierce and hold fast-moving prey. In contrast, bottom-dwelling sharks like the Nurse Shark and Port Jackson Shark have dense, plate-like teeth. These flattened teeth specialize in crushing hard-shelled organisms such as crustaceans and mollusks. Filter-feeding sharks, including Whale Sharks and Basking Sharks, possess thousands of tiny, non-functional teeth, as they do not actively hunt with their mouths.
The Unique System of Tooth Replacement
Sharks are distinct among vertebrates for their continuous tooth replacement system, often described as a “conveyor belt” of teeth. Their jaws contain multiple rows, with new teeth constantly developing behind the functional front row. As a tooth is lost or worn, the tooth behind it moves forward to take its place. This rapid replacement ensures sharks always maintain a sharp, effective set of teeth.
A shark can replace a lost tooth within a day, and younger sharks may replace teeth weekly. Throughout its lifetime, a single shark can shed tens of thousands of teeth. This ongoing process contributes to the abundance of shark teeth found in marine environments.
What Fossilized Shark Teeth Look Like
Fossilized shark teeth are commonly found, offering a glimpse into ancient marine life. Unlike modern white shark teeth, fossils often display darker colors like black, brown, or gray. This coloration results from permineralization, where minerals from the surrounding sediment replace the tooth’s organic material over millennia.
Fossil teeth are usually found without roots, or with roots darker and more robust than modern teeth. They may also appear polished from being tumbled by water currents. They are frequently discovered in locations that were once submerged oceans, including riverbeds, sand pits, and beaches. Their durability and sheer volume make them common vertebrate fossils.