A handful off the 500+ species of shark can survive in river systems but several species are very rarely seen by humans.
For some, the thought of a large fin slicing through the water is enough to put them off wading into the ocean – even just ankle deep.
The fear many people have of sharks is, arguably, unfair – there were 65 unprovoked bites globally in 2025, compared with more than 100 deaths from rip currents in the USA alone.
Do any sharks live in rivers?
But the idea that there’s no chance of coming across a shark once you’ve reached freshwater is also a misconception.
The bull shark is probably the most famous shark to creep into rivers. These massive sharks, which typically grow to around two or three metres long, can survive in salt, brackish and freshwater.
They can do this because of a special ability to keep the right balance of salt and water within their bodies whether they’re swimming in salty or freshwater.
“To keep from losing water and dehydrating in the salty sea, sharks maintain high levels of a substance called urea in their bodies. They also have a special organ that excretes excess salt they absorb from sea water,” explains Marine Science Institute, The University of Texas at Austin, on its website.
“When a bull shark ventures into bays, rivers or lakes, it faces the opposite problem: It must retain vital salt while getting rid of excess fresh water,” they add. “To cope with this change, bull sharks reduce the amount of urea in their body, and their kidneys work overtime, excreting about 20 times more urine – but much less salt – than when they are in salt water.”
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Bulls aren’t the only species that can travel from the sea into rivers, and vice versa. Its relative the Pondicherry shark (Carcharhinus hemiodon) can do this too.
These critically endangered animals are found across the Indo-Pacific but they’re incredibly rare, with the IUCN Red List’s 2021 assessment suggesting there may be fewer than 250 adults left on the planet.
The IUCN says the last reliable record of an individual from this species being found was more than 60 years ago in 1960. “There are reports from 1979, the 1990s, and 2000, but none of these could be verified,” they write.
Shark expert Rex I. De Silva published a paper in 2014 identifying a one-metre individual found in Sri Lanka as a Pondicherry shark, although he notes the specimen didn’t have black markings on its fin which are typical of this species (their dark-tipped pectoral fins look like they’ve been writing with a leaky pen).
Speartooth sharks (Glyphis glyphis), northern river sharks (Glyphis garricki) and Ganges sharks (Glyphis gangeticus) can also survive in rivers. There are three living species of this genus (Glyphis) that have been formally recognised by scientists, although there may be more yet to be described.
They have small eyes. Good vision isn’t that important in murky river systems. They probably rely on ampullae of Lorenzini to detect electrical currents pulsing off prey instead. River sharks are very rare. The Ganges shark (Glyphis gangeticus) is listed as critically endangered, with just 240 adults left on the planet, according to the IUCN Red List’s 2021 assessment. They write: “there is little doubt the population has been severely depleted due to a long history of intensive and largely unregulated riverine and coastal fisheries and other threats in its habitat.
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