The tawny nurse shark, brown and 2.50 meters on average, sleeps under overhangs by day and hunts in the holes of the reef at night. In the Maldives, you find it resting in the crevices of the pinnacles, often in groups; it is listed as Vulnerable and protected like all sharks in the country.
How do you identify a tawny nurse shark?
The tawny nurse shark, Nebrius ferrugineus, is a massive shark with a slightly flattened body, 2.50 meters long on average and up to 3.20 meters. Its color is uniform, tawny to gray-brown on the back and flanks, paler on the belly. The head is broad and flat: the small mouth, set under the snout, carries two nasal barbels. The eyes are tiny, with horizontal pupils, and an even smaller spiracle behind each one. Four gill slits are visible. The two triangular dorsal fins sit far back; the pectorals are long, pointed and sickle-shaped; the tail, with no marked lower lobe, makes up about a third of the body length. You can tell it from the whitetip reef shark by its plain color, its flattened head and its slow swimming close to the bottom.
How does the tawny nurse shark live?
It is a coral reef shark, found from the Red Sea and the Indian Ocean to Japan, northern Australia and Polynesia, from the surface to 70 meters, mostly in the top thirty meters. It lives at night: by day it rests in caves, crevices and under coral blocks, where you often find several packed tightly together. At dusk, it sets off to search the reef. Its pharynx works like a pump: it sucks octopus, small fish, crabs, shrimp, spiny lobsters and sea urchins out of the holes where they hide, and it can also blow a jet of water, which earns it the nickname spitting shark. It is ovoviviparous, with oophagy: the embryos feed on eggs produced by the mother, and a litter has four to eight pups, born at 40 to 60 centimeters.
Where and when can you see tawny nurse sharks in the Maldives?
In the Maldives, you meet it all year round, resting under overhangs and in the crevices of thilas and outer reefs, most often between 5 and 30 meters. By day, you find it stretched out on the sand of a cave, sometimes with others; at night, it cruises slowly over the reef flat looking for octopus, and a night dive is the best way to watch it hunt. It tolerates calm divers who keep their distance, but it leaves its hideout if you push it or if a light hits its eyes.
Is the tawny nurse shark threatened?
The tawny nurse shark is listed as Vulnerable on the IUCN Red List: it grows slowly, breeds little and lives close to shore, where it gets caught in nets and is fished for its fins, skin and liver. In the Maldives, it benefits from the total ban on shark fishing in force since March 2010. Usually harmless, it can inflict a serious bite if disturbed while resting: do not touch it, grab it or pull it out of its cave.
Our tip
Do not disturb it in its hideout: it looks asleep, but it bites hard when touched and does not let go. Watch it from the side, at a distance, and on night dives keep your light out of its eyes. Leave the way clear in front of its cave: that is its exit.