Whitetip reef shark (Triaenodon obesus)

Classification (WoRMS)

Full classification as recorded by WoRMS: Kingdom: Animalia · Phylum: Chordata · Class: Elasmobranchii · Order: Carcharhiniformes · Family: Carcharhinidae · Genus: Triaenodon.

Accepted name: Triaenodon obesus · Authority: (Rüppell, 1837) · Taxonomic status: accepted · AphiaID: 214557.

Synonyms and superseded combinations recorded for this taxon: Carcharias obesus Rüppell, 1837; Traenodon obesus (Rüppell, 1837); Triaenodon apicalis Whitley, 1939; Trianodon obesus (Rüppell, 1837).

Source: World Register of Marine Species (WoRMS) — https://www.marinespecies.org/aphia.php?p=taxdetails&id=214557 (CC BY 4.0). Accessed 2026-09-23.

Biology and life history (FishBase)

Measured values published by FishBase for Triaenodon obesus. Only fields the database actually holds for this species are shown; these are database values, not aquarium guidance.

Maximum length: 213 cm · Common length: 160 cm · Depth range: 0–330 m · Habitat zone: reef-associated · Body shape: fusiform / normal · Vulnerability index: 90 of 100 · Fishery importance: minor commercial · Aquarium trade: never/rarely.

FishBase notes: Sluggish inhabitant of lagoons and seaward reefs where it is often found resting in caves or under coral ledges during the day (Ref. 6871, 58302), or usually on a sand patch, or in a channel (Ref. 37816). More active at night or during slack tide in areas of strong currents (Ref. 37816). Feeds on benthic animals such as fishes, octopi, spiny lobsters and crabs (Ref. 244). Viviparous (Ref. 50449). Travels distances from about 0.3 to 3 km in periods up to about 1 year (Ref. 244). Rarely reported to attack humans, but is potentially dangerous especially when fish had been speared (Ref. 244). Probably fished wherever it occurs (Ref. 244). Caught by inshore longline and gillnet fisheries, and probably adversely affected by dynamite fishing (Ref.58048). Meat and liver utilized fresh for human consumption (Ref. 244). The liver of this shark has been reported as toxic (Ref. 583). One to five 60 cm young per litter (Ref. 1602). Minimum depth reported taken from Ref. 128797.

Source: FishBase species summary (SpecCode 907) — https://www.fishbase.se/summary/Triaenodon-obesus.html (CC BY-NC 3.0 — non-commercial use only). Accessed 2026-09-23.

Distribution and occurrence records (GBIF)

33,607 georeferenced occurrence records for Triaenodon obesus are published through GBIF from 62 countries or marine areas. The map above plots 277 distinct locations from a sample of 3,000 records, omitting 25 inland records that carry an institution's coordinates rather than a collection site; it shows where the species has been observed and reported, not a modelled range.

Most records by country or area: Australia (26,485); Ecuador (1,070); United States of America (831); New Caledonia (557); Maldives (430).

The full country table, WoRMS marine regions and the sampling notes are on this species' Distribution page.

Source: GBIF Occurrence Search (taxonKey 2418054) — https://www.gbif.org/occurrence/search?taxon_key=2418054&has_coordinate=true (records CC0 / CC BY); WoRMS distribution records (MarineRegions) — https://www.marinespecies.org/aphia.php?p=taxdetails&id=214557 (CC BY 4.0); Natural Earth 110m basemap — https://www.naturalearthdata.com/ (public domain). Accessed 2026-09-23.

Conservation status (IUCN Red List)

The IUCN Red List assesses Triaenodon obesus (Rüppell, 1837) as Vulnerable (code VU). No trend, population estimate or threat analysis is given here, because none is available from this source without the Red List API; follow the source link for the full assessment, including its date.

Source: IUCN Red List of Threatened Species (taxon 39384) — https://www.iucnredlist.org/species/39384/0; GBIF IUCN Red List category endpoint (taxonKey 2418054) — https://api.gbif.org/v1/species/2418054/iucnRedListCategory. Accessed 2026-09-23.

Description and natural history (Wikipedia)

During the day, whitetip reef sharks spend much of their time resting inside caves. Unlike other requiem sharks, which rely on ram ventilation and must constantly swim to breathe, this shark can pump water over its gills and lie still on the bottom. At night, whitetip reef sharks emerge to hunt bony fishes, crustaceans, and octopus in groups, their elongate bodies allowing them to force their way into crevices and holes to extract hidden prey. Individuals may stay within a particular area of the reef for months or years, frequently returning to the same shelter. This species is viviparous, in which the developing embryos are sustained by a placental connection to their mother.

Whitetip reef sharks are rarely aggressive towards humans, though they may investigate swimmers closely. However, spear fishers are at risk of being bitten by one attempting to steal their catch. This species is caught for food, though ciguatera poisoning resulting from its consumption has been reported. The IUCN has assessed the whitetip reef shark as Vulnerable, noting its numbers are dwindling due to increasing levels of unregulated fishing activity across its range. The slow reproductive rate and limited habitat preferences of this species renders its populations vulnerable to overfishing.

The whitetip reef shark was first described by the German naturalist Eduard Rüppell as Carcharias obesus, in the 1837 Fische des Rothen Meere (Fishes of the Red Sea). His choice of the specific epithet obesus was curious, given that this shark is actually quite slender. Later in 1837, Johannes Müller and Friedrich Henle moved this species into its own genus Triaenodon, from the Greek triaena meaning "trident", and odon meaning "tooth". As Rüppell did not originally designate a holotype, in 1960 a 31-cm-long specimen caught off Jeddah, Saudi Arabia, was made the species lectotype. Other common names for this shark include blunthead shark, light-tip shark, reef whitetip shark, and whitetip shark.

Once placed in the family Triakidae, the whitetip reef shark is now recognized by most authors as belonging to the family Carcharhinidae on the basis of morphological characters, such as a full nictitating membrane, well-developed precaudal pit, strong lower caudal fin lobe, and scroll-like intestinal valves. Morphological and molecular phylogenetic analyses suggest the whitetip reef shark is grouped with the lemon sharks (Negaprion) and the sliteye shark (Loxodon) in occupying an intermediate position on the carcharhinid evolutionary tree, between most basal genera (Galeocerdo, Rhizoprionodon, and Scoliodon) and the most derived (Carcharhinus and Sphyrna).

The whitetip reef shark is distributed widely across the entire Indo-Pacific region. It was once thought to have existed in the Atlantic Ocean, based on fossil teeth found in North Carolina dated to the Miocene epoch, although subsequent research has suggested that the teeth are of a mackerel shark, and that the whitetip has never colonized the Atlantic. In the Indian Ocean, whitetip reef sharks can be found off of northern KwaZulu-Natal, South Africa and all along the East African coast, from the Horn of Africa to the Red Sea and along the Indian subcontinent (including Sri Lanka). They are found near many major island chains as well, including Madagascar, Mauritius, Mayotte, the Comoros, the Aldabra Group, the Seychelles and the Chagos Archipelago.

In the western and central Pacific Ocean, whitetips occur off South China, Taiwan, and the Ryukyu Islands, south to the Philippines and throughout the entire Coral Triangle, including the coastlines of Indonesia, East Timor and Papua New Guinea. Their range continues south to the northern Australia and the Great Barrier Reef. Whitetips are also found around numerous Pacific atolls and islands, including Melanesia, Micronesia, and Polynesia, north to Hawaii and south to the Pitcairn Islands. They have also been sighted near Midway and Johnston Atolls and Laysan. In the Eastern Pacific, they may be found off the west coasts of Costa Rica and Panama south to the Galápagos Islands, and as far north as Isla Isabel, Isla Socorro, and the southern tip of Baja California (Cabo San Lucas and Cabo Pulmo National Marine Park).

Associated almost exclusively with coral reef habitats, whitetip reef sharks are most often encountered around coral heads and ledges with high vertical relief, and additionally over sandy flats, in lagoons, and near drop-offs to deeper water. They prefer very clear water, and rarely stray far from the bottom during the day. The species is most common at a depth of 8 - 40 m. On occasion, they may enter water less than 1 m deep when foraging; there is an exceptional record of a whitetip reef shark being captured from a depth of 330 m off the Ryukyu Islands.

A relatively small species, few whitetip reef sharks are longer than 1.6 m. The maximum length this species attains is often given as 2.1 m, though this was originally based on visual observations and may be dubious. The maximum reported weight is 18.3 kg. The whitetip reef shark has a slim body and a short, broad head. The snout is flattened and blunt, with large flaps of skin in front of the nares that are furled into tubes. The eyes are small and oval with vertical pupils and prominent ridges above, and are often followed by a small notch. The mouth has a distinct downward slant (imparting a disgruntled expression to the shark), with short furrows at the corners. There are 42–50 tooth rows in the upper jaw and 42–48 tooth rows in the lower jaw. Each tooth has a single narrow, smooth-edged cusp at the center, flanked by a pair of much smaller cusplets.

The first dorsal fin is positioned well back on the body, closer to the pelvic than the pectoral fins. The second dorsal and anal fins are large, about half to three-quarters as high as the first dorsal fin. The broad, triangular pectoral fins originate at or slightly before the level of the fifth gill slit. There is no ridge between the first and second dorsal fins. The lower lobe of the caudal fin is half the length of the upper, which has a strong notch near the tip. The dermal denticles are small and overlapping, usually with 7 horizontal ridges, giving the skin a smooth feel. The coloration is grayish to brownish above and white below, with a pattern of scattered small, dark spots unique to each individual. The tips of the first dorsal fin and upper caudal fin lobe, and sometimes also the second dorsal fin and lower caudal fin lobe, are bright white.

The whitetip reef shark is one of the three most common sharks inhabiting the reefs of the Indo-Pacific, the other two being the blacktip reef shark (Carcharhinus melanopterus) and the grey reef shark (Carcharhinus amblyrhynchos). The habitat preferences of this species overlap those of the other two, though it does not tend to frequent very shallow water like the blacktip reef shark, nor the outer reef like the grey reef shark. The whitetip reef shark swims with strong undulations of its body, and unlike other requiem sharks can lie motionless on the bottom and actively pump water over its gills for respiration. This species is most active at night or during slack tide, and spends much of the day resting inside caves singly or in small groups, arranged in parallel or stacked atop one another. Off Hawaii, these sharks may be found sheltering inside underwater lava tubes, while off Costa Rica they are often seen lying in the open on sandy flats.

Source: Wikipedia: Whitetip reef shark — https://en.wikipedia.org/wiki/Whitetip_reef_shark (CC BY-SA 4.0). Accessed 2026-09-23.

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