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· Indus River system, Pakistan · 3 min read

11 Amazing Facts About the Indus River Dolphin, the Bhulan That Swims on Its Side

In brief

The Indus River dolphin, or bhulan, is a nearly blind freshwater dolphin found only in Pakistan's Indus River system; it swims on its side, hunts by echolocation, is Pakistan's national mammal, and is Endangered with fewer than about 2,000 mature individuals.

Key Takeaways

  • The Indus River dolphin (Platanista minor), or bhulan, is the national mammal of Pakistan and lives only in the Indus River system.
  • It is functionally blind, lacking an eye lens, and navigates entirely by echolocation.
  • It famously swims on its side, trailing a flipper along the riverbed to find prey it cannot see.
  • It was recognised as a separate species in 2021 and is classified Endangered, with about 1,987 mature individuals.
  • Irrigation barrages have fragmented its range and cut its distribution by roughly 80 percent.

Few animals are as strange, as specialised, or as quietly endangered as the Indus River dolphin. Known locally as the bhulan, this nearly blind freshwater dolphin lives in just one river system on Earth and behaves unlike almost any other cetacean. Here are 11 facts that capture what makes it remarkable. For the full picture, see our Indus River dolphin species guide.

1. It is the national mammal of Pakistan

The bhulan holds official status as Pakistan's national mammal, a recognition of how tightly its survival is bound to the Indus River that defines the country.

2. It is functionally blind

The Indus River dolphin has no crystalline lens in its eyes. It can probably sense only the direction and brightness of light, not images. In the silt-choked Indus, eyesight would be nearly useless anyway.

3. It "sees" with sound

Instead of vision, the dolphin relies on a near-constant stream of echolocation clicks to map its surroundings and locate prey hidden in murky water.

4. It usually swims on its side

One of its oddest habits: the bhulan typically swims tilted onto one flank, trailing a flipper along the riverbed, then rolls upright to breathe.

5. Females outsize males

Unusually, females are the larger sex, reaching roughly 2.4 to 2.6 metres, while males stay around 2 to 2.2 metres.

6. It lives in only one river system

The species is overwhelmingly confined to Pakistan's Indus, with only a tiny remnant lingering in India's Beas River.

7. It was named a full species in 2021

Long treated as a subspecies, the Indus River dolphin was recognised as its own species, Platanista minor, after genetic and skull studies published in 2021.

8. Fewer than about 2,000 remain

The 2021 IUCN assessment estimated roughly 1,987 mature individuals, based on a 2017 survey, and lists the species as Endangered.

9. Dams reshaped its world

Irrigation barrages have sliced its once-continuous 3,400 km range into fragments and cut its distribution by around 80 percent.

10. It hunts the river bottom

Its diet is mostly bottom-dwelling fish such as catfish and carp, plus prawns and other invertebrates detected by sonar.

11. Its numbers have clawed back

After dropping to a few hundred animals, decades of rescue and protection have lifted the population toward 2,000, a rare conservation bright spot, though it remains Endangered.

The bhulan survives entirely within Pakistan, one of the countries where our partner-funded teams work. If this dolphin moved you, you can support river-habitat protection that keeps the Indus flowing for its last dolphins.

Frequently Asked Questions

How many Indus River dolphins are left?
The 2021 IUCN assessment estimated about 1,987 mature individuals based on a 2017 survey. The species is Endangered, though numbers have recovered from only a few hundred decades ago.
Why does the Indus River dolphin swim on its side?
Swimming tilted onto one flank lets the dolphin trail a flipper along the riverbed and detect bottom-dwelling prey by touch and echolocation in water where it cannot see. It rolls upright to surface and breathe.
Where do Indus River dolphins live?
Almost entirely in the Indus River system of Pakistan, with a tiny remnant population in the Beas River in India.
W

WARN Research & Conservation Team

World Animal Rescue Network

Published 3 min read · 454 words
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