Ganges Shark

• Maximum lengthAt least 1.8 m (6 ft), probably to just over 2 m (6.5 ft)
• WeightNot recorded; a 2 m river shark would weigh roughly 80–100 kg (175–220 lb)
• LifespanUnknown; no ageing study exists
• Depth rangeShallow river channels and estuaries; marine depth unknown
• DietProbably bony fishes and stingrays
• IUCN statusCritically Endangered (assessed 2021)

How to recognise a Ganges shark

The single most useful feature is the eye. A Ganges shark's eyes are minute, a fraction of the size you would expect on a 2 m shark, and they sit high on the head and tilt upward, so that from the side the animal looks almost eyeless. The head is heavy, with a broad, rounded snout and a wide mouth reaching back past the eyes. The body is stout, the tail stalk thick, and the colour a uniform grey to greyish-brown above and pale below, without spots, bars or fin markings.

The fins separate it from the bull shark that shares its rivers. The first dorsal is tall and triangular with its origin over the rear of the pectoral bases; the second dorsal is unusually large, about half the height of the first, where a bull shark's is a third or less; and the anal fin has a deeply notched rear edge. No interdorsal ridge runs between the two dorsal fins.

The teeth are the final check. The upper jaw carries 32–37 rows of broad, triangular, serrated teeth; the lower jaw 31–34 rows of long, narrow, hooked teeth with smooth edges and spear-like tips, the character that gives the genus its name. A bull shark has fewer, broader lower teeth and much bigger eyes. Rarity, not similarity, is why the two are confused: fishermen on the Hooghly see bull sharks every season and a Ganges shark perhaps once in a career (see how shark teeth are counted).

How big do Ganges sharks get?

Very few Ganges sharks have been measured by a scientist. Specimens of 1.78 m (5 ft 10 in) total length are on record, including an adult, and the accepted estimate for the maximum is a little over 2 m (6.5 ft). A large female landed at Karachi in 2016 and identified by DNA was described as bigger than anything previously examined, which suggests the true ceiling may sit above 2 m, but a reliable measured maximum is still lacking.

The smallest free-swimming individuals known are about 56–60 cm, and that is taken to be the size at birth. Nothing is known about the size at which either sex matures or whether females grow larger than males, though in the closely related speartooth shark and northern river shark both sexes mature at roughly 1.4–1.7 m, and the Ganges shark is unlikely to differ much.

No weight has ever been published. A thick-bodied requiem shark of 2 m weighs somewhere in the range of 80–100 kg (175–220 lb). The size bar below sets the 2 m estimate against a 1.8 m diver.

Where Ganges sharks live

The historic core of the range is the Ganges–Hooghly system of West Bengal in India, where the type specimens were collected in the 1830s and most of the two dozen or so confirmed records since have come from, chiefly around Kolkata. The Mahanadi in Odisha has produced a few. In 2016 a Ganges shark was identified at Karachi fish harbour in Pakistan, extending the range west to the Indus delta.

Genetics widened the map further. The Irrawaddy river shark, known from one specimen taken at Yangon in the 1890s, and the Borneo river shark, known from a handful of animals caught in the Kinabatangan River of Sabah in Malaysia in the 1990s, were shown in 2015 to be the same species, so the Ganges shark also lives, or lived, in Myanmar and north-eastern Borneo.

Within those rivers it is an animal of the lower and middle reaches: turbid, silt-laden channels and estuaries with a tidal influence, in warm water of 25–30 °C, where visibility is measured in centimetres. It is not the "only shark that lives exclusively in fresh water" the old page claimed. The Karachi record came from a marine fishery, its relatives in Australia move between rivers and the sea, and it is best described as a euryhaline species that favours estuaries and river mouths.

What Ganges sharks eat and how they hunt

Not one published Ganges shark stomach analysis exists, so diet is deduced from the jaws, the eyes and the relatives. The narrow, hooked, spear-tipped lower teeth are a fish-grabbing set, designed to pierce and hold a slippery body, and the serrated upper teeth then cut it into pieces. That combination points to bony fishes, such as the catfishes, hilsa and croakers of the lower Ganges, together with the freshwater and estuarine stingrays that the speartooth shark in Australia eats regularly.

The minute eyes tell you how it finds that food. In water where light fails within a hand's breadth, vision is nearly useless, and the Ganges shark has invested instead in the other senses: the ampullae of Lorenzini across the broad snout, which detect the electrical field of a fish or a buried ray; the lateral line, which reads the pressure waves of movement in the channel; and smell. The upward tilt of the eyes suggests it hunts near the bottom and watches for silhouettes overhead.

Its Australian cousins forage along the bottom of tidal channels at night, riding the tide, and the Ganges shark most likely does the same, working the deep scoured bends and confluences where fish gather.

Behaviour and senses

No one has watched a living Ganges shark for longer than the minutes between net and market, so its behaviour is inference. The stocky torso, thick tail stalk and large fins belong to a slow, sustained swimmer that holds position in current rather than a sprinter. River sharks in Australia tracked with acoustic tags stay within a few tens of kilometres of river, move up and down with the tide and the season, and push downstream into estuaries as they grow older; the old claim on this page of mass migrations of "62.1 miles" has no source and has been dropped.

Two adaptations stand out. The tiny eyes are protected by a nictitating membrane, a third eyelid that sweeps across the eye and keeps silt out during feeding. And because sight is so poor, the electrical and lateral-line senses are unusually developed, which is what allows a large predator to operate in water it cannot see through.

Nothing is known about its social behaviour. River sharks generally turn up singly in nets, and the few catches of several Ganges sharks at once, such as the Kinabatangan animals of the 1990s, involved juveniles and may reflect a nursery area rather than a school. Whether adults gather to mate, and where, is unknown.

Reproduction and lifespan

The Ganges shark is presumed to reproduce like every other requiem shark: viviparous, with the embryo's exhausted yolk sac forming a placenta against the wall of the uterus, and the pups born alive and fully formed. That is a safe assumption because the whole family shares it, but it has never been confirmed for this species: no pregnant female has been described in the scientific literature. Litter size, gestation period and breeding season are therefore unknown.

Size at birth is better known, because the smallest specimens on record are 56–60 cm and evidently newborn. Where they are born is a reasonable guess. The juveniles from the Kinabatangan and from the Hooghly were taken in the upper tidal reaches of rivers, well above the sea, which matches the pattern in the speartooth shark of northern Australia: pups are dropped in fresh or nearly fresh water far upstream, where large marine predators are absent, and drift toward the estuary as they grow. The rivers are the nursery, so whatever happens to a river happens to the next generation of Ganges sharks.

Age and growth have never been studied. Related river sharks and requiem sharks of similar size mature at around a decade, breed every second year and live 20–30 years (see how long sharks live), and there is no reason to think the Ganges shark is faster.

Is the Ganges shark dangerous to people?

The honest answer is that it has never been shown to have bitten anyone. The SharkSider database holds no incident attributed to this species, and the international attack files are the same. The reputation is a century old and came from the lower Ganges, where bathers and pilgrims at the ghats were occasionally bitten by "the Ganges shark"; when those cases were re-examined, the culprits were bull sharks, which enter the Hooghly in numbers and have a genuine record of biting people in shallow, turbid water. A stout grey shark in a sacred river got the local name, and the name stuck to the wrong species.

Could a Ganges shark bite? Any 2 m shark with serrated upper teeth is physically capable of injuring a person, and murky water full of bathing people is where mistaken-identity bites happen. But a species known from a few dozen specimens in nearly two hundred years is not a meaningful risk to anybody; you are far more likely to meet a bull shark, and even that is rare. The real incidents from the region are listed on the India attack page, and which species matter is explained in our guide to dangerous sharks.

The SharkSider database has no incident attributed to this species. The database draws on the International Shark Attack File, the Global Shark Attack File and verified local reports, and is updated weekly.

Conservation status

The IUCN Red List classes the Ganges shark as Critically Endangered, a status it has carried for decades and one that the 2021 reassessment, made after the Irrawaddy and Borneo river sharks were merged into the species, confirmed. The population has never been counted; confirmed records number only a few dozen across almost two centuries, most from one river system whose fisheries and flow have been transformed in the meantime. Since November 2023 the whole requiem shark family, this species included, has been on CITES Appendix II, so international trade in its parts requires permits. It is not listed under the Convention on Migratory Species.

India gave it the strongest national protection available in 2001, listing it on Schedule I of the Wildlife (Protection) Act, which makes catching, keeping or selling one a criminal offence. The difficulty is enforcement in a river fished by tens of thousands of small boats with gillnets that cannot tell a Ganges shark from a bull shark, and a fish-market trade in which a rare shark is simply a shark. Pakistan, Myanmar and Malaysia offer no species-specific protection.

The threats beyond fishing are the river's own: dams and barrages that block movement and change flow, water abstraction that shrinks the channels in the dry season, and severe industrial and sewage pollution around Kolkata. Fins and jaws from any large shark still find buyers (see the fin trade and why sharks are endangered). Environmental DNA surveys of the Hooghly and the Kinabatangan are now the best hope of finding out where the last Ganges sharks are.

Similar species and close relatives

The genus Glyphis holds only three living species, all river sharks with the same tiny eyes, tall second dorsal fin and spear-tipped lower teeth. The speartooth shark of northern Australia and New Guinea is the best studied, thanks to Australian tagging work, and is the model for most of what is inferred about Ganges shark biology; it has fewer upper tooth rows and dark pigment on the fin tips. The northern river shark of the Kimberley and Northern Territory is closest in build.

The look-alike that matters is the bull shark, the other big grey shark of the Ganges, Indus, Irrawaddy and Bornean rivers: larger-eyed, with a smaller second dorsal fin and broad lower teeth, and responsible for the bites the Ganges shark was blamed for. Two other Critically Endangered requiem sharks of the region, the Pondicherry shark and the Borneo shark, share its fate of being known from a handful of museum specimens, and the pigeye shark, another stout, blunt-snouted coastal species, is regularly misidentified as a bull shark and occasionally as a river shark in the same fish markets.

• Speartooth Sharkspecies profile
• Northern River Sharkspecies profile
• Bull Sharkspecies profile
• Pondicherry Sharkspecies profile
• Borneo Sharkspecies profile
• Pigeye Sharkspecies profile

Written and reviewed by

SharkSider Editorial Team

A small team focused on researching sharks and making marine biology easy to understand. Every page is reviewed against current species records and the SharkSider attack database, and updated when new incidents or research appear.

Published August 19, 2022 · Last updated September 22, 2026 · No incident attributed to this species in the SharkSider attack database, which is updated weekly.