- Streams of the Andes Mountains converge, eventually forming the Amazon River.
The mightiest river in South America is the Amazon. It has the greatest volume of water and the largest drainage basin of any river in the world. Together with its tributaries, the Amazon drains about one third of South America. Its length is about 4,000 miles (6,400 kilometers)—second only to the Nile River and equivalent to the distance between New York City and Rome. Location and physical characteristics - Boat traffic on the Amazon River near Gurupá, Pará state, Brazil.
The Amazon originates in the icy heights of the Andes Mountains in Peru. From there it flows eastward through Venezuela, Ecuador, Colombia, Bolivia, and Brazil before emptying into the Atlantic Ocean. The river varies in width from 4 to 6 miles (6 to 10 kilometers). Its mouth is more than 150 miles (240 kilometers) wide. The Amazon has more than 1,000 known tributaries. The vast Amazon Basin has an area of about 2.3 million square miles (6 million square kilometers). ClimateThe Amazon flows just south of the equator for most of its course. Therefore, the Amazonian climate is warm, rainy, and humid. The annual rainfall is about 50 inches (130 centimeters), and the average temperature is about 85° F (30° C). At the higher elevations in the Andes, though, temperatures are much lower. Plants and animalsThe dominant feature of the Amazon Basin is the dense tropical rain forest. The river and the forest support an immense variety of plant and animal life. Many of the region's species have not yet been identified. Of all the plant species in the world, almost three fourths can be found in the basin. A great variety of trees make up the rain forest, including palms, broad-leafed magnolias, figs, Brazil nuts, and rubber trees. The tallest trees reach heights of 200 feet (60 meters). Below the trees grow masses of shrubs, creepers, and smaller plants. These include orchids, begonias, ferns, and cacti. The northeastern portion of the basin has extensive savannas, or grasslands, with occasional trees and shrubs. The animal life of the Amazon Basin is as rich as its vegetation. The forest resounds with the cries of monkeys and birds and the whine of insects. Among the vividly colored birds are parrots, macaws, toucans, and parakeets. The most spectacular of the insects are the hundreds of species of butterflies. Notable also is the capybara, a rodent weighing up to 110 pounds (50 kilograms). Other animals of the forest include sloths, tapirs, anteaters, and armadillos. The Amazon Basin also abounds in fish life and reptiles. The fresh water of the Amazon supports about 1,500 to 2,000 species of fishes, including catfish, electric eels, and flesh-eating piranhas. Among the reptiles are the anaconda, a huge snake that crushes its victims; the poisonous coral snake; and crocodiles. PeoplePrior to the arrival of Europeans in the 16th century, the Indian population of the Amazon Basin was about 6.8 million. The Indians lived by farming, fishing, hunting, and gathering fruits and nuts. In the 17th century, the Europeans who attempted to settle the Amazon Basin took many Indians into slavery. Many other Indians died from such European diseases as influenza, measles, and smallpox. By the early 1990s, the Indian population had dropped to about 600,000. Most now live in remote areas. The Amazon Basin now has a mainly urban population. Large cities include Belém, Manaus, and Santarém in Brazil. EconomyPlant products such as rubber, hardwoods, Brazil nuts, and rosewood are major Amazon Basin exports. Manganese ore, diamonds, gold, and petroleum are mined and sold. Some of the fish is marketed locally but some is frozen and sent to other countries. The 3,400-mile (5,400-kilometer) Transamazonian Highway crosses the basin, extending from northeastern Brazil to Peru. This highway together with connecting roads has improved trade within the basin. It has greatly lowered transportation costs and opened up large new areas for development. All highways were designed to connect to the existing water transportation network. HistoryIn 1541 the Spanish explorer Francisco de Orellana became the first European to explore the Amazon River. Afterward he told of encounters with tribes led by women resembling the Amazons of Greek mythology. This comparison is said to have led him to name the river the Amazon. Nearly a century later, Pedro Teixeira went from Belém to Quito, Ecuador, and the region increasingly became known through the explorations of the Portuguese. In 1743 the French naturalist Charles-Marie de La Condamine made a raft trip down the Amazon, during which he made observations of the basin's geography and people.The Amazon Basin continued to attract explorers and scientific investigation into the 21st century. Ecological issuesIn the 20th century, many people became concerned about the rapidly growing population in the Amazon Basin. As settlers cleared the land, the forest shrank dramatically. In the 1990s the Brazilian government and several international groups began efforts to protect parts of the forest from human exploitation and destruction. The destruction of the forest concerned many observers who saw the Amazon Basin as a global resource. The trees of the forest affect the world's climate. Scientists believe that the gas released when large parts of the forest are cleared and burned may contribute to a problem known as global warming. They also warn that the loss of the forest is a threat to the many plants and animals that live there. |