In the deep, swirling rivers of Southeast Asia and Borneo, swims a stingray that is probably the largest freshwater fish in the world.
Capable of growing bigger than a full-size snooker table and weighing as much as a polar bear, this is a river monster with a serious sting in its tail.
- What is the world's largest freshwater fish?
- "Something wasn't right." Diver films giant stingray emerging from seabed with part of its body missing
Urogymnus Polylepsis is an absolute giant and bigger than any saltwater stingray species. A fish caught from the Mekon River in 2022 measured 4m long, 2.2m wide and weighed 300kg. Incredibly, there are reports of fish more than twice that size.
The giant stingray has huge pectoral fins which form what appears to be a singular, rounded body. The fish can ‘flap’ these fins similarly to a stiff-winged bird, in order to swim and also work itself into the sand or soft sediment of the riverbed. Once part-buried, the grey colouration of the upper body and flattened form of the stingray make it difficult to see, although the long, whip-like tail still carries quite the threat.
The stinging spine is positioned on the top of the tail and can measure up to 40cm long. It is coated in toxic mucus and once propelled by a powerful sweep of the tail, is capable of penetrating bone.
- "The 200kg beast ripped off a large part of his calf and nearly severed his leg" – 10 deadliest river animals that can deliver a lethal punch
- 10 deadliest rivers in the world including a 'boiling river' that 'cooks' animals from the inside out
Fortunately, the giant stingray is rarely aggressive and human injuries are unusual, although this is in part due to a dramatic decline in the species’ population.
- This river giant can grow over 1m long, weigh more than 5kg and lay an astonishing 500,000 eggs
- 6 of the world's most venomous fish, from the deadly stonefish to the beautiful and dangerous lionfish
The giant stingray was once more widely spread, but overfishing, alongside habitat degradation, has seen numbers in some parts of its range reduced by as much as 95%. With a low reproductive rate, the average size of adult fish has also fallen, and the ICUN (International Union for the Conservation of Nature) now classify the species as endangered.
Hopefully this leviathan will lurk in the murk of the Mekong and other Asian rivers for a long time to come.
- When scientists went into an underground river in the Philippines, they found a ghostly creature living in the shadows
- Australia’s most terrifying wildlife spectacle: 50 saltwater crocs crammed into one small stretch of river waiting to strike
Top image: slpu9945 / Getty Images
