Scientists today classify river dolphins as endangered species because many populations have declined in recent years as a result of widespread habitat degradation and habitat loss. River dolphins once ranged widely throughout the rivers and coastal estuaries of Asia and South America. Today river dolphins live only in limited portions of the Yangtze, Mekong, Indus, Ganges, Amazon and Orinoco river basins and coastal estuaries in Asia and South America.
River dolphins flouish in zones of quiet water typically found near river confluences.
River dolphins prefer to swim alone or in groups of two and three. They feed on fish and crustaceans. Several species lack the ability to see. All river dolphins use a sophisticated system of sonar clicks' called echolocation to identify mates and prey. In the past river dolphins and people coexisted peacefully along the Mekong, Ganges, Yangtze and Amazon rivers.