South America: natural zones, regions and population

In the lowlands of South America natural zones change with latitude: equatorial forests, subequatorial forests and savannas, grasslands, semi-desert and deserts. The wet equatorial forest of the Amazon basin is called selva (Portuguese for forest) and its territory is Amazonia. Its trees grow in many layers with lianas twining round them; hevea (rubber), cacao, kapok (ceiba) and the very light balsa grow here. Many animals are adapted to life in trees: monkeys, sloths, hummingbirds; the rivers hold the anaconda, piranha and capybara, and the jaguar lives in the forest. In the subtropical south-east lies the pampa, treeless grassland with fertile red soils, rheas and pampas deer. Under the influence of the cold Peru Current the Atacama Desert lies on the Pacific coast, and in the south are the dry Patagonian semi-deserts. In the Andes zones change with height: near the equator, from bottom to top, wet forests, mountain forests, low trees and shrubs, páramo meadows, then bare rock, snow and glaciers. Temperature falls about 6 °C for every 1 000 m of climb, so the snow line near the equator starts at roughly 4 500–5 000 m. The farther a mountain is from the equator the fewer belts it has, because the mountain itself is lower and the climate colder. Animals include the spectacled bear, chinchilla, wild llamas and, on steep slopes, the condor.