Ganges river dolphin

How it lives

There is no single breeding season, though births peak from about October to January. Pregnancy lasts about 8 to 12 months and a single calf is born. The calf stays with its mother for about a year. Both sexes mature at about 10 years. Wild life span is thought to be about 18 to 30 years, and the oldest recorded male was 28. The dolphin swims on its side, tilted at about 10 degrees, and nods its head to search the riverbed. It surfaces every few minutes, and in a survey in Bangladesh single dolphins dived for about 68 seconds on average and groups of three for about 41 seconds.

Where it goes

Ganges river dolphins live in the Ganges, Brahmaputra, Meghna and Karnaphuli river basin across Nepal, India and Bangladesh. They prefer deep pools and eddies, and a study of the basin describes a strongly seasonal movement linked to river flow. In the Bangladesh Sundarbans, their distribution is linked to low salinity, high turbidity and moderate depth. Dolphins have also been surveyed in the Halda, Sangu and Karnaphuli rivers near Chattogram.

We only draw a journey on the map when scientists have tracked it or clearly documented it. For this animal we have not found one yet.

Populations

The IUCN lists the Ganges river dolphin as Endangered (assessed July 2022, status unchanged). The 2022 assessment put numbers at roughly 5,000 adults and juveniles, which is higher than earlier figures because more of the rivers in India, Nepal and Bangladesh were surveyed. Experts still describe a continuing, steady decline. A paper on the basin reports a fall from about 4,000 to 5,000 in 1982 to 3,526 in 2014, with 42 dams and barrages and six lost local populations. Wikipedia reports a 2025 survey that counted 6,324 dolphins in Indian waterways. In Bangladesh, the tidal waterways of the Sundarbans held about 225 Ganges river dolphins in a 2006 survey (Smith et al.), and some major Bangladeshi rivers have not yet been surveyed.