Nurse sharks are a common sight in tropical and subtropical coastal waters, often resting on the seafloor or within reefs. Despite being sharks, a common question arises regarding their potential threat to humans. Generally, nurse sharks do not pose a significant danger to people. They are not aggressive predators towards humans, and no fatal attacks have been recorded.
Diet and Feeding Habits
Nurse sharks are primarily nocturnal, bottom-dwelling predators. They feed mainly on small invertebrates like crabs, lobsters, shrimp, and mollusks, along with small fish and stingrays. They are obligate suction feeders, possessing a small mouth on the underside of their head. This mouth has powerful suction capabilities, allowing them to draw prey from crevices or the seafloor, much like a vacuum.
Their teeth further illustrate their diet. Nurse sharks have numerous rows of small, blunt, serrated teeth. These teeth are adapted for crushing hard shells and gripping small prey, not for tearing the flesh of large animals. Unlike the sharp teeth of predatory sharks, a nurse shark’s teeth are suited for grinding and pulverizing. This dental structure and feeding strategy explain why humans are not a natural part of their diet.
Nurse Shark Temperament and Human Interaction
Nurse sharks are known for their docile, slow-moving nature. They often rest on sandy bottoms or in underwater caves and crevices during the day, sometimes in groups. Their calm disposition leads to interactions with humans, particularly divers and snorkelers. Nurse sharks can bite defensively if provoked, disturbed, or harassed.
Bites occur when individuals attempt to touch, pull their tails, step on them, or try to feed them. These bites are defensive reactions to perceived threats, not predatory attacks. Although their mouths are small, their jaws are strong, and their teeth can cause painful injuries requiring medical attention. Nurse sharks are ranked fourth in documented shark bites on humans due to incautious behavior.
Ensuring Safe Coexistence
Interacting with nurse sharks requires respect for their natural behavior and space. Observe them from a safe distance, maintaining several meters between yourself and the shark. Never attempt to touch, chase, or corner a nurse shark, as these actions can provoke a defensive bite.
Avoid feeding nurse sharks, as this can alter their natural behavior and lead to mistaken identity bites. Being aware of their presence in shallow, warm waters and avoiding sudden movements helps prevent startling them. Following these guidelines allows humans to safely share the marine environment with nurse sharks.