Nurse sharks possess teeth, but their dental structure is vastly different from predatory sharks like the Great White. This bottom-dwelling species has highly specialized teeth adapted to its unique diet and passive hunting strategy. The teeth and jaw mechanism are designed not for cutting or tearing flesh, but for a powerful crushing function. Understanding this anatomy is key to comprehending the nurse shark’s generally docile interaction with humans.
The Anatomy of Nurse Shark Teeth
Nurse sharks have numerous small teeth arranged in a dense, interlocking, “pavement-like” pattern. This structure forms a wide, grinding surface rather than a sharp, serrated edge. Each tooth is small and pointed, often featuring three cusps, with the central cusp being the largest.
They exhibit independent dentition, meaning tooth replacement does not depend on the loss of immediate neighbors, allowing for continuous turnover. The total number of teeth ranges from about 58 to 76 at any time, with multiple rows ready to rotate forward from the inner jaw to replace lost or worn teeth.
How Nurse Sharks Use Their Jaws
The primary function of the nurse shark’s powerful jaws and unique dentition is durophagy—the consumption of hard-shelled organisms. The small, dense teeth work with strong jaw muscles to crush the exoskeletons of prey, rather than slicing through soft tissue like many other shark species. This crushing ability is far more pronounced than any cutting capability.
The feeding process begins with a powerful suction mechanism enabled by the shark’s small mouth and large pharynx. The nurse shark rapidly expands its throat cavity, creating a strong vacuum that pulls in prey from the seafloor or crevices. Once the prey is sucked into the mouth, the pavement-like teeth engage to grind the hard shells before swallowing.
The Typical Diet of Nurse Sharks
The specialized dentition and suction feeding are perfectly suited to the nurse shark’s life as a nocturnal, bottom-dwelling predator. They primarily hunt for benthic invertebrates—organisms that live on the ocean floor. Their diet includes a variety of hard-shelled prey:
- Spiny lobsters, crabs, and shrimp.
- Mollusks, such as marine snails, clams, octopuses, and squids.
- Sea urchins and small bottom fish resting at night.
Nurse sharks use their powerful suction to pull conchs from their shells or extract prey from small holes in coral reefs.
Interaction with Humans
Nurse sharks are considered one of the more docile and non-aggressive shark species. They are generally slow-moving and often rest on the seafloor during the day, contributing to their low threat level toward humans.
Bites are rare and almost always result from the shark being provoked, stepped on, or handled without care by divers or fishermen. When a bite does occur, the shark’s instinct is to clamp down with its crushing jaws, and documented cases exist where the shark refused to release its grip. Although they can inflict serious injury due to their powerful, vice-like bite, there are no verified reports of a nurse shark ever killing a human.