Nurse Shark — Belize
Ginglymostoma cirratum
Quick Fact
Nurse sharks are one of the few shark species that can rest motionless on the seafloor — they pump water over their gills rather than relying on forward motion to breathe.
Filmed during Rowan Byrne's fieldwork in Belize.
About This Species
Unlike most sharks, nurse sharks (Ginglymostoma cirratum) can remain stationary on the seafloor for extended periods. They are one of the few shark species capable of buccal pumping — actively drawing water over their gills — which means they do not need to keep swimming to breathe. Nurse sharks are nocturnal predators, spending much of the day resting in groups under coral ledges or on sandy seabeds.
Why It Matters
Nurse sharks are important reef predators that help control populations of invertebrates and fish. Their presence is an indicator of reef health.
Transcript
Nurse sharks are one of the most misunderstood sharks in the ocean. People see them resting motionless on the seabed and assume they're harmless. And while they're generally docile, they're still wild animals that deserve respect. I've encountered nurse sharks many times in Belize, often tucked under coral ledges or piled on top of each other in shallow water. They're nocturnal hunters — during the day they rest, and at night they use their barbels to probe the sand for crustaceans, molluscs, and small fish. Unlike most sharks, nurse sharks can pump water over their gills while stationary. Most sharks need to keep moving to breathe. Nurse sharks don't. They grow to around four metres and can live for 25 years. Females return to the same shallow-water nursery areas to give birth year after year. The Belize Barrier Reef — the second largest in the world — is home to a remarkable diversity of shark species. Nurse sharks, Caribbean reef sharks, bull sharks, hammerheads. All of them are essential to the health of the reef ecosystem. Belize has done more than most countries to protect its marine environment. Large areas of the reef are now protected. But illegal fishing and climate change remain serious threats. Every shark you see on a reef is a sign that the ecosystem is still functioning. When the sharks disappear, the reef follows.