Amazon River | Facts, History, Location, Length, Animals, & Map
About 2,500 fish species have been found within the Amazon system, but many more remain unidentified. Among the more important commercial species are the pirarucu , one of the world’s largest freshwater fish, and various giant catfish . The small flesh-eating piranha generally feeds on other fish but may attack any animal or human that enters the water. Other animals include caiman , river turtles , river dolphins , and manatees . The Amazon is also home to the semiaquatic capybara , the largest rodent in the world, and the nutria (or coypu).
The Amazon is well known for a number of reasons. It is the greatest river of South America and the largest drainage system in the world in terms of the volume of its flow and the area of its basin. While there is some debate about its length, the river is generally believed to be at least 4,000 miles (6,400 km) long, which makes it the second longest river in the world after the Nile River in Africa . The Amazon is also famous for the rainforest found along its shores. The Amazon Rainforest represents about half of Earth’s remaining rainforest and is the world’s largest biological reservoir, home to more than a million species.
Most researchers believe that it is at least 4,000 miles (6,400 km) long. However, no definitive measure is available because no one is entirely sure where the Amazon ends and begins. Given the complexity of the river system, much of which is in remote areas, researchers have proposed several locations in Peru as its source. As to its end point, the Amazon has three outlets to the Atlantic Ocean : two on the northern side of Marajó Island in Brazil and one to the island’s south that joins the Pará River . Scientists have typically selected one of the northern outlets, since the Pará is an estuary of the Tocantins River , which is technically separate from the Amazon.
The Amazon River is located in the northern portion of South America , flowing from west to east. The river system originates in the Andes Mountains of Peru and travels through Ecuador , Colombia , Venezuela , Bolivia , and Brazil before emptying into the Atlantic Ocean . Roughly two-thirds of the Amazon’s main stream is within Brazil.
Amazon River, Portuguese Rio Amazonas, Spanish Río Amazonas, also called Río Marañón and Rio Solimões, the greatest river of South America and the largest drainage system in the world in terms of the volume of its flow and the area of its basin. The total length of the river—as measured from the headwaters of the Ucayali-Apurímac river system in southern Peru—is at least 4,000 miles (6,400 km), which makes it slightly shorter than the Nile River but still the equivalent of the distance from New York City to Rome. Its westernmost source is high in the Andes Mountains, within 100 miles (160 km) of the Pacific Ocean, and its mouth is in the Atlantic Ocean, on the northeastern coast of Brazil. However, both the length of the Amazon and its ultimate source have been subjects of debate since the mid-20th century, and there are those who claim that the Amazon is actually longer than the Nile. (See below The length of the Amazon.)
The vast Amazon basin (Amazonia), the largest lowland in Latin America, has an area of about 2.7 million square miles (7 million square km) and is nearly twice as large as that of the Congo River, the Earth’s other great equatorial drainage system. Stretching some 1,725 miles (2,780 km) from north to south at its widest point, the basin includes the greater part of Brazil and Peru, significant parts of Colombia, Ecuador, and Bolivia, and a small area of Venezuela; roughly two-thirds of the Amazon’s main stream and by far the largest portion of its basin are within Brazil. The Tocantins-Araguaia catchment area in Pará state covers another 300,000 square miles (777,000 square km). Although considered a part of Amazonia by the Brazilian government and in popular usage, it is technically a separate system. It is estimated that about one-fifth of all the water that runs off Earth’s surface is carried by the Amazon. The flood-stage discharge at the river’s mouth is four times that of the Congo and more than 10 times the amount carried by the Mississippi River. This immense volume of fresh water dilutes the ocean’s saltiness for more than 100 miles (160 km) from shore.
The extensive lowland areas bordering the main river and its tributaries, called várzeas (“floodplains”), are subject to annual flooding, with consequent soil enrichment; however, most of the vast basin consists of upland, well above the inundations and known as terra firme. More than two-thirds of the basin is covered by an immense rainforest, which grades into dry forest and savanna on the higher northern and southern margins and into montane forest in the Andes to the west. The Amazon Rainforest, which represents about half of the Earth’s remaining rainforest, also constitutes its single largest reserve of biological resources.
Since the later decades of the 20th century, the Amazon basin has attracted international attention because human activities have increasingly threatened the equilibrium of the forest’s highly complex ecology. Deforestation has accelerated, especially south of the Amazon River and on the piedmont outwash of the Andes, as new highways and air transport facilities have opened the basin to a tidal wave of settlers, corporations, and researchers. Significant mineral discoveries have brought further influxes of population. The ecological consequences of such developments, potentially reaching well beyond the basin and even gaining worldwide importance, have attracted considerable scientific attention (see Sidebar: Status of the World’s Tropical Forests).
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A River Runs Through It: Fact or Fiction?
The first European to explore the Amazon, in 1541, was the Spanish soldier Francisco de Orellana, who gave the river its name after reporting pitched battles with tribes of female warriors, whom he likened to the Amazons of Greek mythology. Although the name Amazon is conventionally employed for the entire river, in Peruvian and Brazilian nomenclature it properly is applied only to sections of it. In Peru the upper main stream (fed by numerous tributaries flowing from sources in the Andes) down to the confluence with the Ucayali River is called Marañón, and from there to the Brazilian border it is called Amazonas. In Brazil the name of the river that flows from Peru to its confluence with the Negro River is Solimões; from the Negro out to the Atlantic the river is called Amazonas.
