Diving by Numbers
GEOGRAPHICAL DISTRIBUTION
This species is wide-ranging in the Indo-Pacific, occurring along the east coast of Africa from South Africa to the Red Sea, Indian Ocean islands, northern Indian Ocean, including India, Sri Lanka, Myanmar, Vietnam, the Philippines, Australia, New Guinea and Polynesia, Melanesia, Micronesia to the Hawaiian Islands and Pitcairn group. The species is also found in the eastern Pacific, Cocos Islands, Galápagos and Panama to Costa Rica
BUCCAL PUMPING
One of only a few requiem sharks that does not have to continuously swim in order to breathe, the whitetip reef shark uses a method known as buccal pumping to pump water into its mouth and over its gills, enabling it to spend long periods of time resting in caves or on the seabed
SITE FIDELITY
Individuals of this species maintain a small home range for months or even years at a time and often return to the same place day after day to rest
HABITAT
Commonly found resting along the bottom in clear, shallow water surrounding coral reefs, where it is capable of lying motionless for long periods of time. Will often form groups and rest on sandy patches, under ledges or in caves during the daytime, but at night transforms into an active and efficient hunter that patrols the reef and rubble areas in search of prey. Most common at depths between 8–40 metres but has been recorded at 330 metres. Rarely seen at the surface
TOURISM
A common sight on dives in the Pacific, where individuals are normally easy to spot resting on open sandy areas at depths around 20–30 metres. Divers attempting to get close to them must move slowly, as they do not like to be approached and will normally move away when disturbed. To see this species at its most active, divers must visit Cocos Island in Costa Rica, where the sharks have learnt to utilise divers’ torches to help them locate their prey, and can be seen in large numbers at night hunting on the reef
REPRODUCTION
Like other members of its family, the whitetip reef shark is viviparous, meaning the embryos are nourished via a placenta-like like attachment after exhausting their initial yolk supply. After a gestation period of approximately 5 months, 1–5 pups are born measuring 52–60cm in length. Mating has been observed in the wild and in captivity and the reproductive cycle is biennial
WHITE TIP
The whitetip reef shark earns its name from its distinctive white tips on its first dorsal and upper caudal fins. These markings sometimes cause the species to be mistaken for the silvertip shark, although on close inspection the species are visually quite different
DIET
This shark is a specialist at catching benthic prey hiding in caves and crevices at night. Its slender body enables it to wriggle into tight spaces that are inaccessible to other reef sharks where it targets bony fishes, octopuses, lobsters and crabs
PREDATORS
Potential predators include large sharks such as the tiger shark and Galápagos shark, while smaller individuals and juveniles have also been found inside the stomach of other large fish such as the giant grouper (Epinephelus lanceolatus)
SNOUT, JAWS AND TEETH
The head is flattened with a broadly rounded and blunt snout. The mouth has a distinct downward slant and the jaws contain 42–50 rows of teeth in the upper jaw and 42–48 rows in the lower jaw. Each tooth has a single narrow, smooth-edged cusp at the centre, flanked by a pair of much smaller cusplets