The Amazon river dolphin, also known as the boto, bufeo or pink river dolphin, is a species of toothed whale endemic to South America and is classified in the family Iniidae. Three subspecies are currently recognized: I. g. geoffrensis, I. g. boliviensis and I. g. humboldtiana while position of Araguaian river dolphin within the clade is still unclear. The three subspecies are distributed in the Amazon basin, the upper Madeira River in Bolivia, and the Orinoco basin, respectively.
River dolphins are a polyphyletic group of fully aquatic mammals that reside exclusively in freshwater or brackish water. They are an informal grouping of dolphins, which itself is a paraphyletic group within the infraorder Cetacea. Extant river dolphins are placed in two superfamilies, Platanistoidea and Inioidea. They comprise the families Platanistidae, the recently extinct Lipotidae, Iniidae and Pontoporiidae. There are five extant species of river dolphins. River dolphins, alongside other cetaceans, belong to the clade Artiodactyla, with even-toed ungulates, and their closest living relatives the hippopotamuses, from which they diverged about 40 million years ago. Specific types of dolphins can be pink.
The La Plata dolphin, franciscana or toninha is a species of river dolphin found in coastal Atlantic waters of southeastern South America. It is a member of the Inioidea group and the only one that lives in the ocean and saltwater estuaries, rather than inhabiting exclusively freshwater systems. Commercialized areas that create agricultural runoffs and industrialized zones can affect the health of the La Plata dolphin, especially in regards to their contributions of waste and pollution, which can lead to habitat degradation and poisoned food among other concerns.
Oceanic dolphins or Delphinidae are a widely distributed family of dolphins that live in the sea. Close to forty extant species are recognised. They include several big species whose common names contain "whale" rather than "dolphin", such as the Globicephalinae. Delphinidae is a family within the superfamily Delphinoidea, which also includes the porpoises (Phocoenidae) and the Monodontidae. River dolphins are relatives of the Delphinoidea.
Aquatic and semiaquatic mammals are a diverse group of mammals that dwell partly or entirely in bodies of water. They include the various marine mammals who dwell in oceans, as well as various freshwater species, such as the European otter. They are not a taxon and are not unified by any distinct biological grouping, but rather their dependence on and integral relation to aquatic ecosystems. The level of dependence on aquatic life varies greatly among species. Among freshwater taxa, the Amazonian manatee and river dolphins are completely aquatic and fully dependent on aquatic ecosystems. Semiaquatic freshwater taxa include the Baikal seal, which feeds underwater but rests, molts, and breeds on land; and the capybara and hippopotamus which are able to venture in and out of water in search of food.
Boto is a Portuguese name given to several types of dolphins and river dolphins native to the Amazon and the Orinoco River tributaries. A few botos exist exclusively in fresh water, and these are often considered primitive dolphins.
The Bolivian river dolphin is a species of the genus Inia.
The dolphin genus Sotalia is considered to have two member species with the classification of Sotalia guianensis as a distinct species from Sotalia fluviatilis in 2007. This was a result of recent morphometric analyses, as well as mitochondrial DNA analysis.
Pellona harroweri, called the American coastal pellona and the caille, is a species of longfin herring native to the beaches and estuaries of the western Atlantic from Panama to southern Brazil. Some individuals can reach 18 cm, with the average closer to 12 cm. They school in very shallow waters, and are rarely found deeper than 16 m.
The Araguaian river dolphin or Araguaian boto is a South American river dolphin population native to the Araguaia–Tocantins basin of Brazil.
The Guiana dolphin, also known as the estuarine dolphin or costero, is a dolphin found in the coastal waters to the north and east of South America, and east of Central America. It is a member of the oceanic dolphin family (Delphinidae). It can live in both saltwater and freshwater.
The Uatumã Sustainable Development Reserve is a sustainable development reserve in the state of Amazonas, Brazil. The land is owned by the state, but the reserve has a population of about 1,300 people engaged in sustainable agriculture, extraction and fishing.
Piagaçu-Purus Sustainable Development Reserve is a sustainable development reserve in the state of Amazonas, Brazil.
A whitewater river is classified based on its chemistry, sediments and water colour. Whitewater rivers have high levels of suspended sediments, giving the water a pH that is near-neutral, a high electric conductivity and a pale muddy, café au lait-like colour. Whitewater rivers are of great ecological importance and are important to local fisheries. The major seasonal Amazonian floodplains known as várzea receive their water from them.
The Monte Alegre várzea (NT0141) is an ecoregion of seasonally flooded várzea forest along the Amazon River in the Amazon biome.
The Purus várzea (NT0156) is an ecoregion of seasonally flooded várzea forest in the central Amazon basin. It is part of the Amazon biome. The ecoregion is home to a vegetation adapted to floods of up to 12 metres (39 ft) that may last for eight months. There is a great variety of fish and birds, but relatively fewer mammals. Ground-dwelling mammals must migrate to higher ground during the flood season. Threats include logging, cattle farming, over-fishing and mercury pollution from gold mining.
The Iquitos várzea (NT0128) is an ecoregion of flooded forest along rivers in Brazil, Peru and Bolivia in the west of the Amazon biome. The forest is seasonally flooded up to 7 metres (23 ft) by whitewater rivers carrying nutrient-rich sediment from the Andes. The meandering rivers often shift course, creating a complex landscape of oxbow lakes, marshes, levees and bars, with grasslands, shrubs and forests in different stages of succession. During the extended flood periods fish enter the forest in search of fruit. The várzea is accessible by the navigable rivers that run through it, and has suffered from extensive deforestation to extract timber and create pasture for livestock.
Cetaceans form an infra-order of marine mammals. In 2020, approximately 86 species of cetaceans had been identified worldwide. Among these species, at least 35 have been sighted in the wider Caribbean region with very widespread distribution and density variations between areas. Caribbean waters are a preferred breeding site for several species of mysticeti, who live further north the rest of the year. The tucuxi and the boto live at the southern periphery of the Caribbean region in the freshwaters of the Amazon river and surrounding drainage basins.
