SOUTH AMERICA

fourth largest of the world's continents. It is the southern portion of the landmass generally referred to as the New World, the Western Hemisphere, or simply the Americas. The continent is compact and roughly triangular in shape, being broad in the north and tapering to a pointCape Horn, Chilein the south. South America is bounded by the Caribbean Sea to the northwest and north, the Atlantic Ocean to the northeast, east, and southeast, and the Pacific Ocean to the west. In the northwest it is joined to North America by the Isthmus of Panama, which forms a land bridge narrowing to about 50 miles (80 kilometres) at one point. Drake Passage, south of Cape Horn, separates South America from Antarctica. Relatively few islands are associated with the continent, except in the south. These include the glaciated coastal archipelagoes of Argentina and Chile. The Falkland (Malvinas) Islands are east of southern Argentina. To the north, the West Indies stretch from Trinidad to Florida, but these islands usually are associated with North America. Of the remainder, most are small oceanic islands off the coasts of South America, including the Galpagos Islands, Ecuador, in the Pacific Ocean. South America has a total area of about 6,878,000 square miles (17,814,000 square kilometres), or roughly one-eighth of the land surface of the Earth. Its greatest north-south extent is about 4,700 miles, from Point Gallinas, Colom., to Cape Horn; while its greatest east-west extent is some 3,300 miles, from Cape Branco, Braz., to Point Parias, Peru. At 22,831 feet (6,959 metres) above sea level, Mount Aconcagua, in Argentina, near the border with Chile, is not only the continent's highest point but also the highest elevation in the Western Hemisphere. The Valds Peninsula, on the southeastern coast of Argentina, includes the lowest point, at 131 feet (40 metres) below sea level. In relation to its area, the continent's coastlinesome 15,800 miles in lengthis exceptionally short. The name America is derived from that of the Italian merchant and navigator Amerigo Vespucci, one of the earliest European explorers of the New World. The term America originally was applied only to South America, but the designation soon was applied to the entire landmass. Because Mexico and Central America share an Iberian heritage with nearly all of South America, this entire region frequently is grouped under the name Latin America. South America's geologic structure consists of two dissymmetric parts. In the larger, eastern portion are found a number of stable shields forming highland regions, separated by large basins (including the vast Amazon basin). The western portion is occupied almost entirely by the Andes Mountains. The Andesformed as the South American Plate moved westward and forced the oceanic plate to the west under itconstitute a gigantic backbone along the entire Pacific coast of the continent. The basins east of the Andes and between the eastern highlands have been filled with immense quantities of sediment washed down by the continent's great rivers and their tributaries. No other continentexcept Antarcticapenetrates so far to the south. Although the northern part of South America extends north of the Equator and four-fifths of its landmass is located within the tropics, it also reaches subantarctic latitudes. Much of the high Andes lie within the tropics but include extensive zones of temperate or cold climate in the vicinity of the Equatora circumstance that is unique. The great range in elevation produces an unrivaled diversity of climatic and ecological zones, which is probably the most prominent characteristic of South American geography. The original inhabitants of South America are believed to have descended from the same Asiatic peoples who migrated to North America from Siberia during the most recent (Wisconsin) ice age. Few of these peoples, however, survived the arrival of Europeans after 1500, most succumbing to disease or mixing with people of European and (especially in Brazil) African origin. Some parts of the continent are now industrialized, with modern cities, but the people of most regions still follow an agricultural way of life. The wealth of mineral products and renewable resources is considerable, yet economic development in most of the continent lags behind the more industrially advanced regions of the world. Nonetheless, considerable concern has arisen about the rapidly increasing and often destructive exploitation of these resources. Jean P. Dorst C.W. Minkel For discussion of individual countries of the continent, see specific articles by name, e.g., Argentina, Brazil, and Venezuela. For discussion of major cities of the continent, see the articles Buenos Aires, Caracas, Lima, Rio De Janeiro, and So Paulo. For discussion of the indigenous peoples of the continent, see the articles American Peoples, Native; and Pre-Columbian Civilizations. Related topics are discussed in the articles Native American arts; Latin America, history of; and Latin-American literature. fourth largest continent and southernmost of the two main New World landmasses. It covers about one-eighth of Earth's land area. The continent, broad in the north and tapering to a point in the south at Tierra del Fuego, extends about 4,700 miles (7,600 km) from Point Gallinas, Colom., in the north to Cape Horn, Chile (and the nearby Diego Ramrez Islands), in the south. At its broadest point, near where it is crossed by the Equator, South America extends about 3,300 miles (5,300 km) from east to west; four-fifths of its landmass lies within the tropics. Bounded by the Caribbean Sea to the north-northwest, the Atlantic Ocean to the northeast, east, and southeast, and the Pacific Ocean to the west, the continent is separated from Antarctica by the Drake Passage. In the northeast it is joined to North America by the Isthmus of Panama, which forms a land bridge narrowing to about 50 miles (80 km) at one point. Area 6,878,000 square miles (17,814,000 square km). Pop. (1993 est.) 308,770,000. For current history and for statistics on society and economy, see Britannica Book Of The Year. Additional reading General works Broad geographic surveys of the region and of individual countries include Preston E. James and C.W. Minkel, Latin America, 5th ed. (1986); Gilbert J. Butland, Latin America, 3rd ed. (1972); Harold Blakemore and Clifford T. Smith, Latin America, 2nd ed. (1983); and Arthur Morris, South America, 3rd ed. (1987). Jan Knippers Black (ed.), Latin America: Its Problems and Its Promise, 2nd ed. (1991), is a collection of authoritative studies in physical, economic, and political geography. Useful annual publications include the South American Handbook, a travel guide; and South America, Central America, and the Caribbean (irregular), published by Europa Publications. C.W. Minkel Physical and human geography Geology Carlos Schobbenhaus et al. (eds.), Geologia do Brasil (1984), is a thorough account (in Portuguese) of the geology of the continent's largest country. English-language discussions of the continent's geology are found mostly in periodical literature, such as A. Forero Suarez, The Basement of the Eastern Cordillera, Colombia: An Allochthonous Terrane in Northwestern South America, Journal of South American Earth Sciences, 3(23):141151 (1990); Victor A. Ramos, The Birth of Southern South America, American Scientist, 77(5):444450 (1989), and The Tectonics of the Central Andes, in Sydney P. Clark, Jr., B. Clark Burchfiel, and John Suppe (eds.), Processes in Continental Lithospheric Deformation (1988), pp. 3154; and Jorge Julian Restrepo and Jean Francois Toussaint, Terranes and Continental Accretion in the Colombian Andes, Episodes, 11(3):189193 (1988). Victor A. Ramos The land Descriptions of the physical geography of South America are provided in the general works cited above and in E.J. Fittkau et al. (eds.), Biogeography and Ecology in South America (1969); A.C.S. Wright and J. Bennema, The Soil Resources of South America (1965); Jos A.J. Hoffman (compiler), Atlas climtico de America del Sur (1975), with text in Spanish and English; and such classic accounts as Charles-Marie de La Condamine, A Succinct Abridgement of a Voyage Made Within the Inland Parts of South America, trans. from French (1747); and Alexander von Humboldt, Personal Narrative of Travels to the Equinoctial Regions of the New Continent, During the Years 17991804, trans. from French, 7 vol. (181429), available also in later editions.Works on South America's plant and animal life include Adrian Forsyth and Kenneth Miyata, Tropical Nature (1984), an introduction to a number of Neotropical organisms in their forest setting, by two well-traveled naturalists; Jean Dorst, South America and Central America (1967), a well-illustrated natural history; John C. Kricher, A Neotropical Companion (1989), an exploration of the tropical rain forest, tropical savannas, and coastal ecosystems; George Gaylord Simpson, Splendid Isolation: The Curious History of South American Mammals (1980), an authoritative introduction to the evolution of South American mammalian fauna that was later complemented by the so-called Great American Biotic Interchange, in which North American species migrated southward; Michael A. Mares and David J. Schmidly (eds.), Latin American Mammalogy: History, Biodiversity, and Conservation (1991), a collection of articles; Robert S. Ridgely and Guy Tudor, The Birds of South America, vol. 1, The Oscine Passerines (1989), a discussion of identification, habitat, behaviour, and range of the species of the group; Ghillean T. Prance (ed.), Biological Diversification in the Tropics (1982), a collection of technical papers on the biotic refuges in northern South America that were caused by climatic change; and Franois Vuilleumier and Maximina Monasterio (eds.), High Altitude Tropical Biogeography (1986), a series of specialist scientific papers focusing on the adaptive evolution of specific groups of plants, animals, and insects, principally in the Andes. C.W. Minkel Daniel W. Gade The people A general survey of ethnic origins, geographic distribution of the various groups, and racial relations is found in Magnus Morner, Race Mixture in the History of Latin America (1967); and in Marvin Harris, Patterns of Race in the Americas (1964, reprinted 1980). Nicols Snches-Albornoz, The Population of Latin America (1974; originally published in Spanish, 1973); and William M. Denevan (ed.), The Native Population of the Americas in 1492, 2nd ed. (1992), are historical summaries. Darcy Ribeiro, The Americas and Civilization (1971; originally published in Portuguese, 1970), studies the cultural complexes of the Americas. Richard Graham (ed.), The Idea of Race in Latin America, 18701940 (1990), is a history of the concept and of governmental politics in connection with it. A useful reference source on the subject is Robert M. Levine, Race and Ethnic Relations in Latin America and the Caribbean (1980). The most comprehensive and convenient work on all aspects of information about the South American Indians remains the monumental Julian H. Steward (ed.), Handbook of South American Indians, 7 vol. (194659). On indigenous languages, in addition to specific chapters in the previously mentioned works, see Cestmr Loukotka, Classification of South American Indian Languages, ed. by Johannes Wilbert (1968). Joseph H. Greenberg, Language in the Americas (1987), offers a controversial classification that minimizes the number of Indian language families in the Americas. A useful overview is presented in Harriet E. Manelis Klein and Louisa R. Stark (eds.), South American Indian Languages (1985). Demographic dynamics are studied in Walter Willcox (ed.), International Migrations, 2 vol. (192931, reprinted 1961), in which the most complete statistics on mass European immigration before 1930 are interpreted; W.D. Borrie, The Cultural Integration of Immigrants (1959); Richard W. Wilkie, Latin American Population and Urbanization Analysis: Maps and Statistics, 19501982 (1984); Economic Commission for Latin America, Dynamics and Structure of the Human Settlement Process in Latin America and the Caribbean (1984), a United Nations study; and Debra A. Schumann and William L. Partridge (eds.), The Human Ecology of Tropical Land Settlement in Latin America (1989). Gregory W. Knapp The economy General surveys of economic conditions, government policies, foreign economic relations, and social developments include Eliana Cardoso and Ann Helwege, Latin America's Economy: Diversity, Trends, and Conflicts (1992); John Sheahan, Patterns of Development in Latin America: Poverty, Repression, and Economic Strategy (1987); James Dinsmoor, BrazilResponses to the Debt Crisis (1990); Robert N. Gwynne, New Horizons? Third World Industrialization in an International Framework (1990); Pedro-Pablo Kuczynski, Latin American Debt (1988); and Rhys Jenkins, Transnational Corporations and Uneven Development: The Internationalization of Capital and the Third World (1987). Two annuals, Economic and Social Progress in Latin America, prepared by the Inter-American Development Bank; and Economic Panorama of Latin America, prepared by the United Nations' Economic Commission for Latin America and the Caribbean, offer current information. The roles of natural resources, the environment, and agriculture in the economic development of the continent are examined in David Goodman and Michael Redclift (eds.), Environment and Development in Latin America: The Politics of Sustainability (1991); Joseph S. Tulchin and Andrew I. Rudman (eds.), Economic Development and Environmental Protection in Latin America (1991); Michael J. Twomey and Ann Helwege (eds.), Modernization and Stagnation: Latin American Agriculture into the 1990s (1991); John O. Browder (ed.), Fragile Lands of Latin America: Strategies for Sustainable Development (1989); Dennis J. Mahar, Government Policies and Deforestation in Brazil's Amazon Region (1989), a brief treatment; and Merilee S. Grindle, State and Countryside: Development Policy and Agrarian Politics in Latin America (1986). Special studies of other aspects of continental economy include Felipe Larran and Marcelo Selowsky (eds.), The Public Sector and the Latin American Crisis (1991); Rosemary Thorp, Economic Management and Economic Development in Peru and Colombia (1991); Gary Gereffi and Donald L. Wyman, Manufacturing Miracles: Paths of Industrialization in Latin America and East Asia (1990); and Lawrence S. Graham and Robert H. Wilson, The Political Economy of Brazil: Public Policies in an Era of Transition (1990). Ernst C. Griffin Geologic history The geologic history of South America can be summarized in three different developmental stages, each corresponding to a major division of geologic time. The first stage encompassed Precambrian time (3.96 billion to 570 million years ago) and was characterized by a complex series of amalgamations and dispersals of stable blocks of protocontinental crust called cratons. The second stage coincides with the Paleozoic Era (570 to 245 million years ago), during which time the cratons and material accreted to them contributed to the formation first of the supercontinent Gondwana (or Gondwanaland) and then of the even larger Pangaea. The third stage, in which the present continental structure emerged, occurred in the Mesozoic and Cenozoic eras (the last 245 million years) and includes the breakup of Pangaea and Gondwana, the opening of the South Atlantic Ocean, and the generation of the Andean cordillera. The present tectonic framework of South America consists of three fundamental units: the ancient cratons, the relatively recent Andean ranges, and a number of basins. Five cratonsAmazonia, So Francisco, Luis Alves, Alto Paraguay, and Ro de la Platarepresent the Precambrian core of South America, and (with the exception of the Alto Paraguay craton) these now appear as upwarped massifs arrayed from north to south in the immense eastern portion of the continent; a number of other Precambrian crustal blocks also were accreted along the margins of South America over geologic time. The lofty ranges and intermontane plateaus of the Andes rise along the entire western margin of the continent and represent the collision in the Cenozoic Era (the last 66.4 million years) of the Pacific and South American plates brought about by the opening of the South Atlantic. Finally, vast, downwarped, sediment-filled basins are found between the cratons and along the entire eastern margin of the Andes. The Precambrian Precambrian rocks constitute the oldest rocks of the continent and are preserved in the five core cratons. These rocks are represented by high- to low-grade metamorphosed assemblages along heavily deformed belts of plutonic (intrusive), metavolcanic (metamorphosed extrusive igneous rocks), and metasedimentary rocks. Rocks of Archean age (2.5 to 3.8 billion years old) are known in the Amazonia, Luis Alves, and So Francisco cratons, although precisely dated rock samples are scarce. Ages older than 3 billion years have been reported in the Imataca Complex of Venezuela and in the Xingu area of Brazil, both in the Amazonia craton. The oldest rocks found so farwith ages of some 3.4 billion yearsare in the So Francisco craton in the Brazilian state of Bahia. In the other cratons (e.g., the Ro de la Plata craton in Uruguay) the dating of Archean rocks has been inconclusive. Greenstone belts, which are remnants of Archean oceanic crust emplaced in the suture zones (convergent plate boundaries), contain most of South America's known large gold deposits, such as those located near Belo Horizonte, Braz. Two major cycles of crustal deformation occurred in the Precambrian, widely separated in time from each other. The first, called the Trans-Amazonian cycle, took place approximately 2.2 to 1.8 billion years ago; and the second, the Brazilian cycle, between about 900 and 570 million years ago. The economy As a group, the economies of South American nations have changed profoundly since the 1970s. This has come as a result both of external conditions beyond the control of these nations and of internal policy decisions made to produce change. At the most fundamental level, these countries mainly are exporters of relatively low-value primary products and semiprocessed materials and importers of higher-value manufactured goods. Great efforts have been made across the continent to expand the manufacturing sectors and to reduce dependency on imports. From the 1930s until the late 1980s, the majority of South American nations pursued economic development strategies based on a system of import substitution. National governments used such measures as tariff and price policies to encourage domestic industries and protect them from external competition. They also created joint ventures with private capital and established state-owned enterprises, especially in the heavy industries, utilities, and transportation. They provided high subsidies for social programs in areas such as education and public housing. Furthermore, national spending on armaments and defense soared during periods of military rule. Nations borrowed from foreign private banks and international lending institutions, such as the World Bank and the Inter-American Development Bank, to fund existing programs while also trying to expand their economic productivity through investments in areas such as transportation, energy generation, industrialization, and agricultural modernization. However, many countries lived well beyond their means through the wholesale borrowing of funds at high interest rates on the world market. Consequently, they were forced to borrow more and more money just to service the interest payments that accumulated annually on their outstanding debt, thus creating the so-called debt crisis. With the debt crisis, economic chaos befell many South American nations. After decades of substantial progress in its economic development, the region as a whole regressed significantly in the 1980s. Between 1980 and 1990, gross domestic product (GDP) per capita measured in constant dollars declined for every South American nation except Brazil, Colombia, and Chile. For a part of this same period, inflation rates skyrocketed in many nations, exceeding 3,000 percent per year in some instances. Currency devaluation, economic austerity programs, and governmental disinvestment were the most commonly used remedies to check these problems. The severity of their problems and the demands of their lenders have prompted most South American countries to initiate fundamental restructurings of their economies. These reorganizations are in accord with neoliberal, or free-market, economic theory, which has come to dominate the region's economic planning and decision making in the 1990s. Emphasis has been placed on stimulating economic growth while selling state-owned enterprises to private investors and eliminating or severely curtailing support for social programs. The long-term goal is to increase productivity, reduce governmental expenditures, and diversify economic activities. Regional economic integration also has taken on new importance. The impact of these changes is not yet clear, but their most dramatic effects are felt by those lowest on the socioeconomic ladder. Ernst C. Griffin Resources Mineral resources South America is relatively rich in mineral resources. However, they are highly localized: few nations have a good balance of fuels and raw materials within their boundaries, and two countries, Uruguay and Paraguay, are nearly devoid of mineral wealth. The land Relief South America South America has two major mountain systems of contrasting nature. Bordering the Pacific Ocean to the west, the geologically young cordilleras of the Andes extend along the entire continent from north to south. Stretching along the continent's northern and eastern sides are the ancient Guiana and Brazilian highlands, which are much lower in elevation and slope gently to the west; farther south are the Patagonian plateaus. Lowlandsthe basins of the Orinoco, Amazon, and Paraguay-Paran rivers and the plains of the Pampasdivide the highlands from one another. Taken as a whole, the relief of the continent shows a great imbalance: the major drainage divide is far to the west along the crest of the Andes. Thus, rain that falls only 100 miles (160 kilometres) east of the Pacific may flow to the Atlantic, 2,500 miles away. The Andes Mountains The ranges of the Andes Mountains, about 5,500 miles long and second only to the Himalayas in average elevation, constitute a formidable and continuous barrier, with many summits exceeding 20,000 feet (6,100 metres). The Venezuelan Andesthe northernmost range of the systemrun parallel to the Caribbean coast west of Caracas, before turning to the southwest and entering Colombia. In Colombia the Andesnow trending generally to the north and southform three distinct massifs: the Cordilleras Oriental, Central, and Occidental. The valley of the Magdalena River, between the Oriental and the Central ranges, and the valley of the Cauca River, between the Central and the Occidental ranges, are huge rift valleys formed by faulting rather than by erosion. An aerial view of the Andes in Colombia shows, within relatively short distances, a succession of hot lowlands interspersed with high ranges with snowcapped peaks. In Ecuador the Andes form two parallel cordilleras, one facing the Pacific and the other descending abruptly eastward toward the Amazon basin, crowned by towering peaks. Between the ranges lies a series of high basins. These ranges continue southward into Peru, where the relief becomes considerably more complex; the highest of the Peruvian peaks is Mount Huascarn (22,205 feet) in the Cordillera Blanca. Beginning to the south of Lima and extending through western Bolivia, the Andes again form two distinct ranges. Between them lies the Altiplano, a vast complex of high plateaus between 12,000 and 15,000 feet in elevation and as much as 125 miles wide. The Altiplano forms a maze of valleys, hills, and vast plains without equivalent except in Tibet. Water accumulates in closed basins to form marshes and lakes, the largest of which is Lake Titicaca on the border of Peru and Bolivia. This central region of the Andes has been dissected by several large rivers, all of which have cut spectacular gorges down the eastern slopes. Farther to the southalong the border between Chile and Argentinathe Andes form a single but complex chain with many of the system's highest peaks, including Mount Aconcagua; south of Aconcagua, elevations gradually diminish. In southern Chile a part of the cordillera descends beneath the sea, forming innumerable islands with steep slopes. The Andes have been deeply carved by glaciers, particularly in the south. Glaciers still occupy some 1,900 square miles (4,900 square kilometres), constituting a huge ice cap with long terminal tongues running into lakes or into the sea. The Andes are studded with numerous volcanoes that form part of the Circum-Pacific volcanic chain, often called the Ring of Fire. Earthquakes are frequent. Almost every major city has been devastated at least once by earthquake, even along the coastal plains, where clear signs of recent vertical movement are visible. The people Ethnic origins and migrations Four main components have contributed to the present-day population of South AmericaAmerican Indians (Amerindians), who were the pre-Columbian inhabitants; Iberians (Spanish and Portuguese who conquered and dominated the continent until the beginning of the 19th century); Africans, imported as slaves by the colonizers; and, finally, postindependence immigrants from overseas, mostly Italy and Germany but also Lebanon, South Asia, and Japan. Indians Before the beginning of the epoch of European exploration and conquest in the early 16th century, South America was almost completely occupied by diverse peoples. Nearly all of these cultural groups practiced agriculture, and most exhibited an extraordinary understanding of their physical environment that had been developed over thousands of years. Although areas such as deserts, mountain peaks, and tropical rain forests appeared to be uninhabited, most of these places were occupied at least occasionally. The societies with the greatest complexity of social organization and densest population tended to be located along the Pacific coast, in the adjacent Andes, and along the major rivers of the Amazon basin. Less complex societies were located away from the rivers and mountains, and nomadic hunting groups were found in the Pampas, Patagonia, and southern Chile. Agriculture-based village culture and social organization came first to the tropical lowlands of the Amazon basin and valleys of coastal Ecuador and Colombia (c. 3000 BC). This culture included religious temple-mound complexes, fine ceramics (based partly on earlier technology for making fire-engraved containers out of bottle gourds), and farming such crops as cassava (manioc) and corn (maize) on periodically flooded plains and levees. These areas eventually became organized into complex chiefdoms containing dense populations, supported in some cases by raised fieldsbroad planting surfaces separated by ditches that enhanced the fertility of the soil while limiting the possibility of fungal diseases and waterlogging. The practice of agriculture spread to the desert coast of Peru and Chile and then into the higher elevations of the Andes, and new technologies appeared. In coastal areas, elaborate irrigation networks supported ceremonial centres and (later) true cities such as Chan Chan (near present-day Trujillo on the northern coast of Peru), the capital of the Chim state. Coastal Peruvian and Ecuadorian cultures (such as Moche and Nazca) produced superb ceramic art and finely woven textiles. In coastal Chile the Mapuche (Araucanian) culture effectively occupied its region through farming and hunting. In the highlands, fertile soils of volcanic ash were cultivated with the digging stick and a type of foot plow called the chaquitaclla. Highland soils also were improved by constructing long earthen irrigation canals or (in the Central Andes) some of the world's most elaborate and beautiful stone-walled terracing. In most parts of the Andes, areas of high population density were organized into chiefdomssuch as the Chibcha of Colombia and the mound (tola) builders of Ecuadorled by powerful, paramount lords. Early cities and empires first developed around Huari (Wari) in south-central Peru and Tiahuanaco in western Bolivia, but the last and best-known empire was that of the Inca (Inka). Called Tawantinsuyu, the Inca state expanded from its homeland in the Cuzco Valley of south-central Peru north to what is now southern Colombia and south to the Maule River in central Chile (the northern limit of the Mapuche culture). The Inca easily conquered the desert coastal cultures by threatening their water supplies but never succeeded with the chiefdoms of the Amazon basin and of coastal Ecuador. Thus, when Inca expansion was halted by the Spanish in the 1530s, the empire was long but narrow, confined to the Andes and Pacific coast. This empire did not include all of the advanced agricultural cultures of the continent, which continued north into Venezuela, east into the Amazon basin, and south into the Mapuche area. Certain areas of South Americanotably in the more remote parts of the interior, away from the main riverswere occupied by simpler village cultures based on shifting cultivation, an agricultural practice still used in many of these areas. Nomadic hunter tribes were located in areas of present-day Uruguay and Argentina and in the extreme south (Tierra del Fuego and Cape Horn). Although these cultures appeared to be simple in organization and technology, they were well adapted to hunting wild animals (e.g., the guanaco), fishing, and gathering edible plants in a harsh environment. The number of Indians at the time of the conquest is uncertain: estimates vary from 8 to 100 million for North, South, and Central America combined (for the Inca, from 3 to 32 million). More recent estimates that put South America's preconquest population at about 20 million seem more realistic. Equally controversial is the origin of South America's Indians. Most anthropologists believe that they are descended from people who migrated to North America from Asia between about 60,000 and 20,000 years ago, having crossed the Bering Strait separating northeastern Asia and northwestern North America. It is not known when humans first arrived in South America, although it is fairly certain that people were present in Chile by 11,000 BC.