Amazon river dolphin widespread river dolphins. They are present in six countries in South America: Bolivia, Brazil, Colombia, Ecuador, Peru, and Venezuela, in an area covering about . The boundaries are set by waterfalls, such as the Xingu and Tapajós rivers in Brazil, as well as very shallow water. A series of rapids and waterfalls in the Madeira River have isolated one population, recognized as the subspecies "I. g. boliviensis", in the southern part of the Amazon basin in Bolivia. They are also distributed in the basin of the Orinoco River, except the Caroni River and the upper Caura River in Venezuela. The
American River American River The American River (Río de los Americanos during the period before 1847 ruled by Mexico) is a 120-mile-long river in California that runs from the Sierra Nevada mountain range to its confluence with the Sacramento River in the Sacramento Valley. Via the Sacramento River, it is part of the San Francisco Bay watershed. This river is fed by the melting snowpack of the Sierra Nevada and its many headwaters and tributaries, including the North Fork American River, the Middle Fork American River, and the South Fork American River. The American river is known for the discovery of gold