The Ganges river dolphin is one of the world's few truly freshwater cetaceans, and it is effectively blind: its eyes lack a crystalline lens, so it navigates the silt-laden rivers of the Indian subcontinent almost entirely by echolocation [Sinha & Kannan 2014]. Remarkably, it emits some of the lowest-intensity biosonar clicks measured in any toothed whale—an apparent adaptation to shallow, acoustically cluttered water [Jensen et al. 2013]. Long treated as a single South Asian species, it was formally separated from the Indus river dolphin in 2021 on genetic and morphological grounds [Braulik et al. 2021]. Today it is listed as EN (Endangered) on the IUCN Red List, with a population estimated at roughly 3,500–5,000 individuals and an inferred continuing decline [Kelkar et al. 2022].
Biology and Identification
Platanista gangetica (Lebeck, 1801) is an obligate freshwater odontocete in the monogeneric family Platanistidae [Braulik et al. 2021]. Adults typically measure 2.0–2.6 m in length and weigh roughly 70–90 kg, with females generally larger than males [Sinha & Kannan 2014]. The body is robust and brownish-grey, with a markedly elongated, forceps-like rostrum bearing numerous sharp interlocking teeth, a low triangular dorsal ridge rather than a true fin, and broad paddle-shaped flippers [Sinha & Kannan 2014].
The species' most distinctive trait is its vision: the eye lacks a lens and functions only to sense light direction and intensity, so the animal is functionally blind [Sinha & Kannan 2014]. To compensate, it relies on a near-continuous stream of echolocation clicks to detect prey and obstacles. Jensen et al. [2013] measured a mean apparent source level near 184 dB re 1 µPa—one to two orders of magnitude lower than comparable marine dolphins—interpreted as an adaptation to short detection ranges in turbid, shallow rivers.
The dolphin frequently swims on its side, trailing a flipper along the riverbed, a behaviour thought to aid prey detection in murky water [Sinha & Kannan 2014]. Its diet is dominated by fish and invertebrates, including catfish, carp, gobies, prawns and other benthic prey taken throughout the water column [Sinha & Kannan 2014]. Reproduction is slow: females bear a single calf after a gestation of roughly 9–11 months, calving is broadly distributed across the year, and the long inter-birth interval combined with late maturity makes populations slow to recover from losses [Sinha & Kannan 2014; Kelkar et al. 2022].
Habitat and Range
The Ganges river dolphin inhabits the Ganges–Brahmaputra–Meghna and Karnaphuli–Sangu river systems of South Asia, occurring in India, Bangladesh and Nepal [Kelkar et al. 2022]. It is restricted to fresh water and favours deep pools, channel confluences, eddy counter-currents and sharp meanders where prey concentrate and where water depth persists through the dry season [Sinha & Kannan 2014; Das et al. 2025]. It is a lowland, plains-river specialist, generally absent from fast, shallow upland reaches.
Historically the species ranged widely and continuously across these basins, but its distribution has become increasingly fragmented over the past century [Kelkar et al. 2022]. Dams and barrages have divided once-continuous populations into smaller, partly isolated segments, and the species has been extirpated or reduced in several tributaries and upstream reaches where it formerly occurred [Sinha & Kannan 2014; Das et al. 2025]. Seasonal flow regulation now strongly shapes where dolphins can persist, with many animals concentrating in remaining deep-water refuges during the low-water season [Das et al. 2025]. The Convention on Migratory Species lists the species, reflecting the cross-border nature of its riverine range and the need for coordinated basin-scale management [CMS 2024].
In accordance with NRWL sensitive-species policy, specific site locations, seasonal movement details, and den or nest coordinates are not disclosed in this article.
Conservation Status
The Ganges river dolphin is listed as EN (Endangered) on the IUCN Red List, assessed in 2022 under criteria reflecting a small, fragmented and declining population [Kelkar et al. 2022]. The assessment estimates a total of roughly 3,500–5,000 mature and immature individuals across the species' range; while expanded survey coverage has refined the count upward relative to some earlier figures, the underlying trend is inferred to be one of continuing decline driven by persistent, range-wide threats [Kelkar et al. 2022]. Earlier reviews documented a fall from an estimated 4,000–5,000 animals in the early 1980s to around 3,500 by the 2010s [Sinha & Kannan 2014].
The species is listed on CITES Appendix I, the strictest category, which prohibits commercial international trade in the animal and its parts [CITES 2024]. It is additionally protected under national law—in India it is a Schedule I species under the Wildlife (Protection) Act, 1972, and was declared the National Aquatic Animal of India in 2009 [MoEFCC/WII 2020]. The 2021 taxonomic revision elevating the Indus river dolphin (Platanista minor) to full species status means conservation assessments and recovery planning now treat P. gangetica as a distinct, separately managed species [Braulik et al. 2021].
Threats
Multiple, often interacting, pressures drive the species' decline [Kelkar et al. 2022; Sinha & Kannan 2014; Das et al. 2025]:
- River fragmentation by dams and barrages. Instream barriers split populations into smaller isolated units, block movement, and reduce dry-season flow and pool depth that dolphins depend on [Sinha & Kannan 2014; Das et al. 2025].
- Fisheries bycatch (entanglement). Accidental capture in gillnets is a leading source of mortality, because dolphins sharing prey-rich water with fishers are readily entangled [Kelkar et al. 2022; Das et al. 2025].
- Prey depletion. Overfishing and altered flow reduce the fish and invertebrate stocks the dolphins require, lowering carrying capacity [Das et al. 2025].
- Water abstraction and flow regulation. Diversion for irrigation lowers dry-season water levels, shrinking and isolating usable habitat [Sinha & Kannan 2014].
- Pollution. Agricultural runoff, industrial effluent and domestic waste degrade water quality, and persistent contaminants can accumulate in this apex riverine predator [Sinha & Kannan 2014].
- Vessel traffic and proposed waterways. Increased boat movement and channel-dredging schemes raise risks of disturbance, noise and collision in core habitat [Das et al. 2025].
- Directed take. Although now illegal, opportunistic killing for oil or as a fishing-bait attractant has historically contributed to losses in parts of the range [Sinha & Kannan 2014].
What Is Being Done
A range of government and scientific programmes target the species' recovery. In India, Project Dolphin was launched in 2020 by the Ministry of Environment, Forest and Climate Change to monitor populations and threats and to coordinate basin-scale conservation of riverine and coastal dolphins [MoEFCC/WII 2020]. The species also benefits from habitat-specific protected areas, most notably the Vikramshila Gangetic Dolphin Sanctuary on the Ganga, which safeguards a designated river stretch under India's Wildlife (Protection) Act [MoEFCC/WII 2020].
At the regional, scientific level, the IUCN Cetacean Specialist Group developed a multi-year Conservation Action Plan for the Ganges river dolphin, setting out priorities for survey, threat mitigation and transboundary cooperation [Smith et al. 2010]. The 2022 IUCN Red List reassessment itself provides the standardized population and threat baseline used to guide these efforts [Kelkar et al. 2022], while the 2021 taxonomic revision ensures recovery planning is directed at the correct, distinct species [Braulik et al. 2021]. Recent peer-reviewed status surveys—such as work on the lower Ganga—feed updated abundance and threat data back into management and recommend measures including bycatch reduction, flow maintenance and habitat protection [Das et al. 2025]. Because the species' range spans India, Bangladesh and Nepal, it is also covered by the Convention on Migratory Species, supporting coordinated international action [CMS 2024].
How Readers Can Help
Readers can contribute in practical, evidence-based ways. Recording verified river-wildlife sightings on open biodiversity platforms such as iNaturalist or GBIF-linked surveys helps researchers track distribution and seasonal occurrence, provided no sensitive precise locations are publicized for vulnerable groups. Supporting and citing peer-reviewed science and official agency assessments—rather than unverified claims—strengthens the information base that conservation decisions rest on [Kelkar et al. 2022; Das et al. 2025].
Engagement with water-management and river-development policy is especially relevant for this species, since flow regulation and instream barriers are central threats; informed public comment during environmental review processes can encourage habitat-sensitive planning [Sinha & Kannan 2014]. Consumers and anglers can favour sustainable, legally compliant fisheries practices that reduce gillnet bycatch risk. Finally, sharing accurate information about the species and the rivers it depends on—framed around healthy, well-managed river ecosystems—helps build the broad constituency that long-term freshwater conservation requires.
References
[Braulik et al. 2021] Braulik, G.T., Archer, F.I., Khan, U., Imran, M., Sinha, R.K., Jefferson, T.A., Donovan, C. & Graves, J.A. (2021). Taxonomic revision of the South Asian River dolphins (Platanista): Indus and Ganges River dolphins are separate species. Marine Mammal Science, 37(3), 1022–1059. https://doi.org/10.1111/mms.12801
[CITES 2024] CITES (2024). Platanista gangetica — Appendix I. Convention on International Trade in Endangered Species of Wild Fauna and Flora, Checklist of CITES Species. https://checklist.cites.org/#/en/search/output_layout=alphabetical&level_of_listing=0&show_synonyms=1&show_author=1&show_english=1&scientific_name=Platanista+gangetica
[CMS 2024] Convention on Migratory Species (2024). Platanista gangetica species page. CMS Secretariat, UNEP, Bonn. https://www.cms.int/en/species/platanista-gangetica
[Das et al. 2025] Das, B.K., Bhakta, D., Johnson, C., Chanu, T.N., Ramteke, M., Chauhan, S.K., Ray, A., Nandy, S., Kunui, A., Roy, S. et al. (2025). Status of Ganges River dolphin Platanista gangetica (Lebeck, 1801) in the lower stretch of the Ganga River, India, with emphasis on threats, conservation, and recommendations. Frontiers in Ecology and Evolution, 13, 1523537. https://doi.org/10.3389/fevo.2025.1523537
[Jensen et al. 2013] Jensen, F.H., Rocco, A., Mansur, R.M., Smith, B.D., Janik, V.M. & Madsen, P.T. (2013). Clicking in shallow rivers: short-range echolocation of Irrawaddy and Ganges River dolphins in a shallow, acoustically complex habitat. PLOS ONE, 8(4), e59284. https://doi.org/10.1371/journal.pone.0059284
[Kelkar et al. 2022] Kelkar, N., Smith, B.D., Alom, M.Z., Dey, S., Paudel, S. & Braulik, G.T. (2022). Platanista gangetica. The IUCN Red List of Threatened Species 2022: e.T41756A50383346. https://dx.doi.org/10.2305/IUCN.UK.2022-1.RLTS.T41756A50383346.en
[MoEFCC/WII 2020] Ministry of Environment, Forest and Climate Change / Wildlife Institute of India (2020). Project Dolphin and the Gangetic Dolphin (National Aquatic Animal of India). National Mission for Clean Ganga, Government of India. https://wii.gov.in/nmcg/priority-species/mammals/ganges-river-dolphin
[Sinha & Kannan 2014] Sinha, R.K. & Kannan, K. (2014). Ganges River Dolphin: an overview of biology, ecology, and conservation status in India. AMBIO, 43(8), 1029–1046. https://doi.org/10.1007/s13280-014-0534-7
[Smith et al. 2010] Smith, B.D., Braulik, G. & Sinha, R.K. (eds.) (2010). The Conservation Action Plan for the Ganges River Dolphin 2010–2020. IUCN Cetacean Specialist Group. https://iucn-csg.org/wp-content/uploads/2010/03/DolphinCAP_27092010_editSS1.pdf