Ask people in India where sharks live. Most of them will say the sea, near Goa or the Andamans. Almost nobody will say the Ganga. But a shark lives in this river. I think it is one of the most remarkable animals in the country.
India's seas have between about 80 and more than 150 shark species. The number changes with the method of counting. Only two of these species can live in a river for a long time.
The first is the bull shark. It usually lives in salt water, but it can live in fresh water better than almost any other shark. The second is a true river shark. It almost never leaves the river. This is the Ganges shark, Glyphis gangeticus.
A body made for muddy water
The Ganges shark is part of a very small and very old family of river sharks. This family is one of the rarest groups of sharks in the world.
The shark can grow to about 9 feet. Its body is made for one task: catching fish in muddy river water. Its eyes are very small, because the silt in the Ganga lets in almost no light. Its teeth are thin and narrow. They hold fish. They cannot tear into an animal as large as a person.
The wrong shark got the blame
For many decades, people blamed this shark for attacks in the Ganga and the Hooghly. It got a reputation as a man-eater.
But almost every time, the real attacker was the bull shark. The bull shark is much heavier and much more aggressive. Its teeth are wide and triangular, and they are made for large prey.
The records go back more than 150 years. They show only one attack that a Ganges shark possibly made, in 1868. Nobody ever confirmed that it was this species.
So rare that it is almost a ghost
The species is disappearing. In 2021, the IUCN put the Ganges shark in the Critically Endangered category. Scientists think that fewer than 250 adult sharks are alive [IUCN Red List].
Three things push it toward extinction. Gillnet fishing catches it. Dams cut its river into pieces. Pollution makes its water worse.
People see this shark so rarely that ten years or more can pass between confirmed records. In February 2016, a female shark appeared at the Sassoon Docks fish market in Mumbai. She was 266 cm (8'7") long, and she was already dead and for sale.
It was the first confirmed record of the species in more than ten years. Shark scientist Rima Jabado and her team identified it. They used three features: the round snout, the very small eyes and the shape of the fins [Journal of Fish Biology, 2018].
Why you should know about it
The Ganges shark is a shy river shark. It eats fish and has very small eyes. For 100 years, people blamed it for attacks that the bull shark made. During the same time, its numbers fell toward extinction. If this shark disappears, I think the main reason will be that almost nobody knew it was there.
