River dolphins make their homes in some of the greatest rivers on the planet, sometimes navigating long distances between feeding and breeding areas with the seasonal shifts linked to water levels. The eight tropical and subtropical river basins where they are found are: the Amazon and Orinoco in South America, and the Ganges-Brahmaputra-Meghna, Indus, Yangtze, Ayeyarwady , Mahakam and the Mekong in Asia.
This interactive map allows you to explore these river basins. Click on any of the river basin outlines below to reveal a pop-up window with quick links to information about the river dolphin species found there, as well as to selected resources that can be used in conservation efforts for each featured basin and species. For more detailed information on resources, visit the Downloadable Resources or Scientific Literature sections of this site.
Amazon / Orinoco river basin
The Amazon river is the largest river of South America. Covering 6,300,000 km2, its basin has the largest drainage system in the world and extends into Bolivia, Brazil, Colombia, Ecuador, French Guiana, Guyana, Peru, Surinam, and Venezuela. On this website, when we refer to the Amazon river basin we also include the 2,267 km Tocantins-Araguaia river in Brazil.
The Orinoco basin covers 880,000 km2, with 75% being in Venezuela and 25% in Colombia. It is the fourth largest river in the world by discharge volume of water.
The Amazon river dolphin lives in both the Amazon and the Orinoco basins. The tucuxi river dolphin lives only in the Amazon basin.
Indus river basin
The Indus River is one of the largest in the world, draining an area of 1,165,000 km2. While its source lies in Tibet and part of its upper course runs through India, the vast majority of the river basin is in Pakistan.
The Indus River is home to the Indus river dolphin.
The Ganges-Brahmaputra-Meghna (GBM) is a transboundary river system spanning five countries: Bangladesh, Bhutan, China, India, and Nepal. The GBM river system is home to about 670 million people and is the third largest river basin in the world in terms of freshwater flow.
The Ganges river dolphin lives in this river system.
Ayeyarwady river basin
The Ayeyarwady River, also known as the Irrawaddy, is the principal river of Myanmar and its most important commercial waterway. The Ayeyarwady river basin covers 413,710 km², of which 91% lies within Myanmar, 5% in China, and 4% in India.
It is home to one of the three riverine subpopulations of the Irrawaddy dolphin.
Mekong river basin
The Mekong River is 4,350 km long, flowing from its source on the Tibetan Plateau in China through Myanmar, Thailand, Laos PDR, Cambodia and Viet Nam. Its river basin covers more than 810,000 km2. Among Asian rivers, only the Yangtze and Ganges have larger minimum flows.
A small stretch of the river in Cambodia is home to one of the three riverine subpopulations of the Irrawaddy dolphin.
Yangtze river basin
The Yangtze River in China is the third longest river in the world. Its basin drains an area of 1,808,500 km2 from its source in the Tibetan Plateau to the East China sea. The Yangtze region is home to more than 400 million people and the river is one of the world’s busiest waterways.
The river is home to the world’s only freshwater porpoise, the Yangtze finless porpoise. It once shared the river with the Yangtze river dolphin – last seen in 2002 and now considered to be functionally extinct.
Mahakam river basin
The Mahakam River is the largest river in East Kalimantan, Indonesia, with a length of 980 km and a catchment area of 77,100 km2. The river has been an important navigation waterway from ancient times until today.
The river is home to one of the three riverine subpopulations of the Irrawaddy dolphin.
© WWF-Brazil / Adriano Gambarini
The Amazon River dolphin is a unique freshwater species found only in the rivers of South America.
© WWF Mohd Shahnawaz Khan
The Ganges river dolphin is known as the “Tiger of the Ganges” for the role it plays as a top predator, and an ecosystem indicator species; much like a tiger does in a forest.
© Nyal Mueenuddin / WWF-Pakistan
Indus river dolphins are also known as the blind dolphins because over millions of years they have lost the use of their eyes.
© naturepl.com Roland Seitre, WWF
The Irrawaddy dolphin is found in marine, brackish, and freshwater environments throughout southeast Asia. The name is derived from the first specimens that were described from the Ayeyarwady river in Myanmar.
© Jessica de Melo IDSM
Tucuxis overlap in range with Amazon river dolphins inhabiting the central region of the Amazon river basin.
© Justin Jin / WWF-US
The Yangtze finless porpoise is the only freshwater porpoise in the world. It can only be found in the Yangtze River, the longest river in Asia.