3 Types of Dolphins in India

Dolphins in India

There are 3 types of Dolphins in India – the Ganges river dolphin, Indus River dolphin, and Irrawaddy dolphin. All three are classified as Endangered or Critically Endangered due to declining populations. These shy aquatic mammals have specially adapted to freshwater environments like rivers and lakes across parts of South Asia.

Gangetic dolphins live only in the Ganges-Brahmaputra river systems while the Indus River dolphin, found mostly in Pakistan, also has a small population in Punjab, India. Irrawaddy dolphins have an isolated pocket in the Chilika Lake lagoon in Odisha. Less than 250 of each species remain in the wild globally.

River dolphins have distinctive features like flexible necks and long beaks that allow effortless gliding while chasing prey underwater. They use echolocation clicks to navigate and hunt for fish in the muddy riverbeds along their limited habitats. Though largely solitary, they occasionally come together in small protective groups.

3 Types of Dolphins in India

Population of Dolphins in India

3 Type of Dolphins in India

1. Gangetic Dolphin

The Gangetic dolphin, also called the Ganges river dolphin, is a freshwater dolphin found in the Ganges-Brahmaputra-Meghna and Karnaphuli-Sangu river systems in Nepal, India, and Bangladesh. These rivers and their many tributaries used to be home to Gangetic dolphins throughout their range. But now the species is extinct from most of its early habitat.

Currently, only an estimated 3,500-5,000 Gangetic dolphins remain. Due to declining numbers and population fragmentation, the species is listed as Endangered by the IUCN Red List.

Physical Characteristics of Gangetic Dolphin

The Gangetic dolphin has a long thin snout and rounded belly. Their bodies are stocky, and they have large flippers compared to oceanic dolphins. Adults have smooth, hairless skin that is gray-brown in color. The females are bigger than males, growing over 2 meters long and weighing up to 170kg, compared to 2.12m and 150kg for males.

They have tiny eyes that function only to detect light, so Gangetic dolphins are essentially blind. To navigate and hunt in the muddy river waters, they use echolocation by emitting ultrasonic sound waves from their blowholes. This produces a “susu” noise that gives them one of their alternate names.

Behavior & Biology of Gangetic Dolphin

Gangetic dolphins usually live alone or in small groups of 2-3 individuals. They generally stay in the deeper parts of rivers and tributary confluences. Their flexible necks allow them to easily hunt fish and shrimp near the river bottom.

Dives last 30-120 seconds. Then they briefly surface to breathe through their blowholes before diving again. Gangetic dolphins breed year round, with most calves born in winter. After 8-9 months gestation, the mothers give birth to a single calf every 2-3 years. The young calf stays with its mother until it is weaned. Adults breed from age 10 onwards and may live up to 30 years.

Threats & Conservation for Gangetic Dolphin

Major threats to Gangetic dolphins include habitat loss from dams/barrages blocking rivers, mortality from getting tangled in fishing nets, pollution from industry/farming, and hunting for meat and oil. Their fragmented populations and declining numbers have led to an Endangered conservation status.

Legal protections for Gangetic dolphins exist in India, Nepal and Bangladesh. There are also some conservation efforts like the Vikramshila Gangetic Dolphin Sanctuary in Bihar, India established specifically to protect the species. But a lot more action is still needed to conserve this rare freshwater dolphin. Their future remains uncertain without greater international cooperation.

2. Indus River Dolphin

The Indus River dolphin is a freshwater dolphin that lives only in the lower parts of the Indus River in Pakistan and the Beas River in Punjab, India. Historically, they were more widespread in the river systems of the region. But loss of habitat means they now occupy just 20% of their former range.

With an estimated population between 1,200-1,800, Indus River dolphins are classified as Endangered by the IUCN Red List. They continue to face threats from human activities like fishing and development projects.

Physical Characteristics of Indus River Dolphin

Indus River dolphins have a distinctive stocky body shape with a rounded forehead called a “melon”. They grow around 2 meters long and weigh 150-200kg. Their skin color is mostly gray on the back and pale pinkish or white on the underside.

They have tiny eyes that can only sense light, so Indus River dolphins rely on echolocation clicking sounds to “see” their surroundings and hunt prey. Their flexible necks allow greater head movement to help echolocate. These dolphins also sometimes swim on their sides, especially in shallow water areas.

Behavior & Biology of Indus River Dolphin

Indus River dolphins live alone or in loose groups of 2-10 individuals. They generally prefer murky, deep river habitats with strong currents, but will move into tributaries during monsoon flood season.

Their average dive lasts 30-90 seconds. Indus River dolphins use echolocation to find fish, prawns and crabs to eat along the riverbed. Sometimes groups work together to surround schools of fish. They surface about every minute to breathe through their blowholes.

Reproduction happens year-round, peaking in late autumn when river volume is high. After a 9 month gestation, females give birth to a single calf. The young stay with their mothers for one year until weaned. Indus River dolphins reach sexual maturity between ages 6-10 and may live around 30 years.

Threats & Conservation

Major threats include habitat loss from irrigation dams/canals fragmenting populations, mortality from entanglement in fishing gear, and pollution from industry/farming runoff. Noise and disturbance from vessel traffic are also concerns. Their limited numbers and habitat have led to an Endangered conservation status.

Legal protections exist for Indus River dolphins in Pakistan and India. But their populations continue to decline. Recently, conservation attention has increased through measures like declaring them the national mammal of Pakistan. But greater action is still required to save the species from extinction.

3. Irrawaddy Dolphins

The Irrawaddy dolphin (Orcaella brevirostris) is a unique freshwater dolphin found in parts of South and Southeast Asia. Unlike most dolphins that live in the ocean, Irrawaddy dolphins are adapted to river habitats like the Ayeyarwady in Myanmar, Mekong in Cambodia and Chilika lake in Odisha.

Irrawaddy dolphins are classified as Endangered on the IUCN Red List. Once more widespread, their distribution is now patchy and limited to small pockets across their range. However, according to a report by the World Wildlife Fund (WWF), only around 250 Irrawaddy dolphins remain in three isolated river populations, and they face the highest risk of extinction

Physical Characteristics of Irrawaddy Dolphins

Irrawaddy dolphins have short round heads without a beak, giving them expressive-looking faces. Their flexible necks allow greater head movement while echolocating. They have a grey coloration overall, with a lighter grey belly, and grow around 2-2.75m long and 90-200kg in weight.

Unlike most dolphins, Irrawaddy dolphins have large paddle-shaped flippers and tail fins. These help them maneuver in shallow muddy river waters. Their distinct look helps identify them in the wild.

Behavior & Biology of Irrawaddy Dolphins

Irrawaddy dolphins form small social groups of 2-10 individuals in river habitats, sometimes gathering in larger groups of 30. They communicate using a variety of clicks and whistles. These dolphins may also display behaviors like breaching, tail slapping or spitting jets of water while feeding or courting.

On average, Irrawaddy dolphins dive and surface every 1-2 minutes. Females mature by age 9, have a 14 month gestation period and give birth to a single calf every 2-3 years. Some individuals may live up to 30 years. Mothers stay close to calves for one year until weaned off nursing.

Feeding & Human Cooperation

Irrawaddy dolphins are opportunistic feeders, eating a wide variety of river fish and crustaceans. Their preference is bony fish and fish eggs from riverbeds. They often work cooperatively while hunting, herding fish by circling and spitting water (IUCN article).

In Myanmar’s Ayeyarwady river, Irrawaddy dolphins display a unique “cooperative fishing” behavior with local fishermen. They signal when to cast nets, then herd fish towards the boats for an easy group meal.

Threats & Conservation of Irrawaddy Dolphins

Major threats Irrawaddy dolphins face include habitat loss from dams/mines, mortality from entanglement in fishing nets and gear, pollution from pesticides/fertilizers washing into rivers, and boat collisions.

Legal protections exist in some areas, but many river dolphin populations continue to decline. Conservation recommendations include enforcing fishing regulations, expanding protected habitat, and promoting community monitoring programs to save these rare freshwater dolphins. Their future remains uncertain without dedicated rescue efforts across their limited range.

Conclusion

In conclusion all three dolphins suffer major threats like fishing net entanglements, habitat destruction from dams/canals, and pollution from agricultural runoff or industrial waste. Few concerted conservation efforts exist currently to actively save India’s endangered river dolphins. But greater protections and community awareness programs focused on these charismatic species will be key to their survival. Their future remains tenuous without dedicated rescue initiatives across the region.