Fish
Nurse Shark
Ginglymostoma cirratum · also called nurse sharks
A nurse shark lies motionless on the sea floor through most of the day, indistinguishable at a glance from any other patch of shadow beneath a reef ledge. After dark it becomes something else entirely, using powerful suction to vacuum crabs and small fish straight out of crevices no biting predator could reach as cleanly.
Overview
The nurse shark, Ginglymostoma cirratum, is a docile, bottom-dwelling shark found in warm coastal waters across the Americas and West Africa. It rests by day and hunts at night using powerful suction feeding to extract prey from tight crevices.
Calm by day, effective by night
Between its notably docile daytime temperament and its genuinely specialised nighttime suction-feeding technique, the nurse shark has built a reputation as one of the more approachable, if still wild, sharks divers regularly encounter resting in plain sight.
Status
Vulnerable — declining in parts of its range from fishing pressure and coastal habitat degradation, though more secure within protected areas.
Nurse Shark: common questions
Is a nurse shark dangerous to humans?
A nurse shark is generally considered one of the more docile shark species, often resting motionless on the sea floor and showing little inclination toward aggression, though like any wild shark it can bite defensively if directly provoked, cornered, or handled carelessly, so appropriate caution and respect are still recommended around wild individuals.
How does a nurse shark catch prey hidden in crevices?
A nurse shark uses powerful suction feeding, rapidly expanding its mouth and throat cavity to generate strong suction capable of drawing prey directly out of tight reef crevices or sandy burrows, a method well suited to extracting hidden crustaceans, small fish, and mollusks that would be difficult to reach through biting alone.
Why does a nurse shark rest motionless during the day?
A nurse shark typically spends much of the daylight hours resting motionless on the sea floor, often in groups within a favoured shelter site, conserving energy before becoming considerably more active at night, when it relies on its barbels and suction feeding technique to hunt effectively in the dark.
Why is the nurse shark considered Vulnerable?
Nurse shark populations have declined in parts of their range due to historical and ongoing fishing pressure, including both targeted catches and incidental bycatch, along with habitat degradation affecting the coastal reef and shallow water areas the species depends on, contributing to its Vulnerable conservation status.