Lowlands make up nearly half of Brazil. By far the largest lowland is the Amazon Basin, or Amazonia, which spans most of northern and western Brazil. The land is generally rolling throughout most of the basin. Only the floodplains along the Amazon and its tributaries are flat. Virtually all the land is densely forested.
The Pantanal, in western Brazil south of the Mato Grosso Plateau, is also a sizable lowland but small compared to the Amazon Basin. It lies within the headwaters area of the Paraguay River and forms an extension of Bolivia's and Paraguay's grassy Chaco. Much of the Pantanal is swamp and marshland.
Coastal lowlands and plains lie along the Atlantic coast south of the Amazon River's mouth. They are, however, generally narrow and discontinuous because highlands closely parallel the coast and, in places, extend eastward to the sea. In the far south of Brazil, in Rio Grande do Sul state, the coastal plain widens into a broad rolling lowland that merges south and west with the grassy plains of Uruguay.
Two highland regions make up the rest of Brazil. The largest is the Brazilian Highlands, an enormous plateau, upland, and mountainous area covering most of south of the Amazon lowlands. Some parts of the Brazilian Highlands, particularly in the north and west, are made up of broad, rolling terrain dotted irregularly by low rounded hills. Parts of the eastern Brazilian Highlands consist of low, indistinct mountain ranges; other parts are extremely rough and formidable, with complex ridges and ranges. The highest and most rugged part is the Serra da Mantiqueira, northwest of Rio de Janeiro, where several peaks rise more than 9,100 feet (2,770 m) above sea level.
The Great Escarpment section of the Brazilian Highlands—a region of sharply rising escarpments, mountains, and ridges—parallels and at places reaches the coast. It has a mean elevation of about 5,000 feet (1,520 m) and extends more than 1,000 miles (1,600 km) from Salvador in Bahia state to Porto Alegre in the far south. Mountains along the Great Escarpment include the Serra do Mar, south of Rio de Janeiro, and the Serra dos Orgãos, north of Rio.
Brazil's other highland region, the Guiana Highlands, lies north of the Amazon lowlands and extends into Brazil from Venezuela, Guyana, Suriname, and French Guiana. It is a virtually undeveloped and isolated area, about which relatively little is known. Near the Venezuelan border is Pico da Neblina, Brazil's highest mountain, rising 9,888 feet (3,014 m) above sea level.
The Amazon River drains about three-fifths of Brazil, as well as large areas beyond the Brazilian border. In length, the Amazon ranks second among the rivers of the world, after the Nile. By volume of water carried, it is overwhelmingly the largest. Major tributaries include the Tocantins, Xingu, Tapajós, Madeira, and Negro. Because of its great depth, the Amazon is navigable by large oceangoing ships as far as Manaus and by smaller ships much farther inland.
Northeastern Brazil, formed by the easterly bulge of the continent, is drained primarily by the São Francisco and Parnaíba rivers. Most of the rivers in southern and southeastern Brazil are part of the Paraná-Paraguay and Uruguay river systems, which drain southward and enter the Atlantic in the vicinity of Buenos Aires, Argentina. Few rivers flow into the Atlantic south of Bahia state because of the barrier formed by the Great Escarpment. There, most rivers flow westward as part of the Paraná system.
Iguassu Falls, on the Iguassu River at the Argentine border, is probably Brazil's most spectacular natural feature. Hundreds of cascades, separated by wooded areas, form a crescent 2.5 miles (4 km) in length and plunge as much as 237 feet (72 m) into a narrow gorge.
There are no large natural freshwater lakes in Brazil, only man-made reservoirs created mainly for hydroelectric power. Most of the reservoirs are in the eastern part of the Brazilian Highlands, inland from Rio de Janeiro and São Paulo. The largest is Sobradinho Reservoir on the São Francisco River, northeast of Salvador.
In the far south are a number of coastal lagoons, largest of which is Patos Lagoon. It is as much as 150 miles (240 km) long and up to 40 miles (65 km) wide.
Brazil, crossed by the Equator in the north and by the Tropic of Capricorn in the south, has both tropical and subtropical climates. The coolest period is June to September, the hottest from December to March.
The lowlands of the Amazon Basin have a tropical rainy climate, with moderately high temperatures, much rainfall, and high relative humidity throughout the year. At Belém, for example, near the mouth of the Amazon River, temperatures average close to 80° F. (27° C.) during all months of the year. Annual rainfall averages well over 80 inches (2,030 mm). Some east coast areas have a similar climate, but are more comfortable because of sea breezes that bring relief from the sultry weather.
The highlands of Brazil have somewhat greater temperature variations than the Amazon Basin. These variations increase generally with distance from the Equator and with increased elevation—the higher the elevation, the cooler the climate. South of the Equator, highland climates are marked by distinct rainy and dry seasons, the dry season coming during the cooler months. Annual rainfall throughout most of the highlands is substantially less than in the Amazon Basin. Some windward mountain slopes, however, have exceptionally heavy rainfall. The dry season is most pronounced in the interior of the northeast, where prolonged droughts occur. The droughts, however, are sometimes broken by heavy rains and severe flooding.
The far south of Brazil has a more temperate climate than the rest of the country. It is marked by a greater range of temperatures during the year and fairly evenly distributed precipitation. Frosts occur as far north as São Paulo state; occasional light snow falls at the higher elevations.
is as varied as the climates of Brazil. Most of the Amazon Basin and the coastal areas between Salvador and Santos are covered by lush tropical rain forests, or selvas. Growing here in great profusion are thousands of species of trees, vines, and other plants, many of which are found nowhere else in the world. Few forests are so extensive. In some areas, particularly along the highways in the Amazon Basin, the rain forests are rapidly being cleared to provide land for settlement and farming.
Subtropical forests, known as mata, cover parts of the Brazilian Highlands. In the wetter areas they consist primarily of tall stands of luxuriant broadleaf evergreen trees. In drier areas there is a sparser growth of generally scrubby deciduous trees. Northeastern Brazil, where droughts frequently occur, has stunted, rather sparse forests, called caatingas, of thorny, drought-resistant trees.
The central and western parts of the Brazilian Highlands are covered by vast savannas, grasslands with scattered trees and wooded areas. Found in the four southernmost states are pine forests in the higher areas and vast open grasslands elsewhere. The grasslands, called campos, resemble the pampas of Argentina.
is extremely varied and includes stingless bees; anteaters; tapirs; monkeys; jaguars; raccoons; bats; and brilliantly colored parakeets, parrots, and toucans. Hundreds of species of butterflies and moths have been identified. Deer roam the grasslands, and dolphins and sea cows swim in the lakes. Snakes include boa constrictors, rattlesnakes, and anacondas. In São Paulo, the Butantan, or Snake, Institute prepares antivenin for use throughout the world.
The Amazon River teems with hundreds of species of fish and other animals. Angelfish, crocodiles, lungfish, huge catfish, and flesh-eating piranhas thrive in the warm river waters.