Ganges shark facts for kids
Quick facts for kids Ganges sharkTemporal range: Miocene-recent
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Glyphis
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| Species: |
gangeticus
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| Glyphis gangeticus inhabits the Ganges-Hooghly River system | |
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The Ganges shark (Glyphis gangeticus) is a very rare and critically endangered shark. It lives in the fresh waters of the Ganges River and Brahmaputra River systems in India and Bangladesh. People often confuse it with the more common bull shark (Carcharhinus leucas). Bull sharks also live in the Ganges River.
Unlike most other sharks, the Ganges shark lives only in fresh water. This makes it one of the world's only true freshwater sharks! Scientists still don't know much about this mysterious animal because it is so hard to find.
Contents
Shark Family Tree
Scientists group the Ganges shark with other "river sharks" in the Glyphis genus. For a while, two other sharks, the Borneo river shark (Glyphis fowlerae) and the Irrawaddy river shark (Glyphis siamensis), were thought to be separate species.
But recent genetic studies have shown that these sharks are actually the same species as the Ganges shark. This means the Ganges shark's home range is much larger than first thought. It now includes areas like Pakistan, Myanmar, Borneo, and Java.
Borneo River Shark
The Borneo river shark was only known from the Kinabatangan River in Borneo. It could grow to about 78 cm (31 in) long. Only 13 of these sharks were ever found by scientists. Even though fishermen remembered seeing them, no new ones have been found since 1996.
Irrawaddy River Shark
The Irrawaddy river shark was known from just one shark found in the Irrawaddy River in Myanmar. It was caught a long time ago, in the 1800s. This shark was about 60 cm (24 in) long. It looked a lot like the Ganges shark. However, it had more bones in its spine (209 versus 169) and fewer teeth (29/29 versus 32–37/31–34).
What the Ganges Shark Looks Like
The Ganges shark is a type of "requiem shark." It has a strong body with two dorsal fins (fins on its back) and one anal fin (fin on its belly). The first dorsal fin is much larger than the second one. It is usually a plain grey or brownish color, with no special patterns.
Its snout (nose area) is wide and rounded. Its mouth is long and wide, reaching back towards its eyes. The eyes are very small. This suggests the shark is good at seeing in murky, muddy water, like the Ganges River.
Special Features
You can tell a Ganges shark apart from other sharks by its teeth. Its front lower teeth are shaped like claws, with sharp edges. Also, its second dorsal fin is only about half the size of its first dorsal fin.
Where Ganges Sharks Live
As its name suggests, the Ganges shark mostly lives in the rivers of eastern and northeastern India. This includes the Hooghly River and parts of the Ganges, Brahmaputra, and Mahanadi rivers. They usually live in the middle or lower parts of these rivers.
While it's possible for them to be in shallow ocean areas near river mouths, no one has ever officially seen a Ganges shark in the ocean. Many old records of this shark were actually other types of sharks, especially bull sharks. Finding a real Ganges shark is very rare. For example, after 2006, one wasn't seen again for over ten years until 2016.
Habitat and Life
The Ganges shark lives only in freshwater rivers and estuaries (where rivers meet the sea). We don't know much about what they eat. Their small eyes and thin teeth suggest they mostly eat fish. They are likely very good at using other senses, like hearing and smell, to find food in the murky water.
Some scientists think these sharks might swim along the river bottom. They might look up for prey that stands out against the sunlight from above. However, in the Bay of Bengal, some Ganges sharks were found to eat a lot of stingrays, which live on the bottom.
Reproduction and Life Cycle
Ganges sharks are probably viviparous. This means the mother gives birth to live young, like mammals, instead of laying eggs. The babies get their food from a yolk sac inside the mother.
We don't know how many babies they have or how long they are pregnant. But like other river sharks, they likely grow slowly and have small litters. This makes them very sensitive to dangers like fishing.
Do They Migrate?
Some researchers believe Ganges sharks might travel long distances, over 100 km (62 mi), up and down rivers. However, this movement is probably not for breeding. Young Ganges sharks have been found in the Hooghly River, which suggests they might be born in fresh water.
Conservation Efforts
The Ganges shark is on the IUCN Red List as critically endangered. This means it is at a very high risk of disappearing forever. Scientists believe there are fewer than 250 Ganges sharks left. We urgently need to study the rivers to find out how many are truly left.
Main Threats
River sharks are very sensitive to changes in their homes. The Ganges shark lives in a small area that is heavily impacted by human activities. The biggest threats are:
- Overfishing: People catch them for their meat and fins.
- Pollution: The rivers are polluted by human waste and chemicals.
- River Use: More boats and human activity disturb their habitat.
- Dams and Barrages: These structures block their movement and change the river flow.
The oil from Ganges sharks is also used as bait for fishing. Their fins are thought to be part of the Asian shark fin trade.
What's Being Done to Help?
In 2001, the Indian government tried to protect all shark and ray species. Later, this rule was changed to protect 10 specific species, including the Ganges shark. They are now protected under India's Wildlife Protection Act. However, it's hard to enforce these rules because many local fishermen still catch them.
Scientists recommend more surveys of fishing areas to understand how many Ganges sharks are being caught. This will help them figure out the best ways to protect these rare animals.
Ganges Sharks and Humans
Many people fear the Ganges shark as a "man-eater." But most attacks in the Ganges River are likely caused by the bull shark, not the Ganges shark. Bull sharks are known to swim far into freshwater and can live in the same areas. Since the Ganges shark is so rare, it's very unlikely for humans to even encounter one.
Also, the Ganges shark's teeth are different from a bull shark's. The Ganges shark has thinner, sharper teeth, which are better for catching fish. Bull sharks have stronger, wider teeth, which are more suited for eating larger prey. This also suggests the Ganges shark is less likely to attack humans.
Images for kids
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An old drawing of a Ganges shark.
See also
- List of sharks
- List of critically endangered fishes
