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Peoples
who are indigenous to the Americas are known as the American Indians . The name
Indian was first applied to them by Christopher Columbus, who believed
mistakenly that the mainland and islands of America were part of the Indies, in
Asia. The Native Americans of North America are believed to be descendants of
the Mongoloids, early hunters and gatherers who migrated from Asia to North
America in waves possibly from as early as 30,000 BC. These Stone Age peoples crossed an ice-age land bridge
across what is now the Bering Strait during the Pleistocene epoch.
It is estimated that at the time of the first European contact, North and South America were inhabited by more than 90 million people: about 10 million in America north of present-day Mexico; 30 million in Mexico; 11 million in Central America; 445,000 in the Caribbean islands; 30 million in the South American Andean region; and 9 million in the remainder of South America. These population figures are a rough estimate (some authorities cite much lower figures); exact figures are impossible to ascertain. By the time European colonists began keeping records, the Native American populations had already been drastically reduced by war, famine, forced labour, and epidemics of diseases introduced through contact with Europeans.
Native Americans
are physically most similar to Asian populations and appear to have descended
from Asian peoples who migrated across the Bering Strait land bridge during the
part of the Quaternary period known as the Ice Age, beginning perhaps some
30,000 years ago. Like other peoples with Mongolian characteristics, Native
Americans tend to have light-brown skin, brown eyes, and dark, straight hair.
They differ from Asians, in the classification of races however, in their
characteristic blood types. Because many Native Americans today have had one or
more European-Americans or African-Americans among their ancestors, numerous
people who are legally and culturally Native American may look fairer or darker
than Mongolian peoples or may have markedly non-Mongolian facial features.
Over the thousands
of years that indigenous peoples have lived in the Americas, they have
developed into a great number of local populations, each differing somewhat
from its neighbours. Some populations (such as those on the Great Plains of
North America) tend to be tall and often heavily built, whereas others (for
example, many in the South American Andes and adjacent lowlands) tend to be
short and broad-chested; furthermore, every population includes people who vary
from the average. Some physical characteristics of Native American populations
have been influenced by diet or by the environmental conditions of their
societies. For example, the short stature of some native Guatemalans seems to
result at least in part from diets poor in protein; the broad chests and large
hearts and lungs of native Andeans represent an adaptation to the rarefied
atmosphere of the high mountains they inhabit.
Evidence of human
migration indicates that the first peoples to cross into the Americas, coming
from north-eastern Siberia into Alaska, were carrying stone tools and other
equipment typical of the middle and end of the Palaeolithic period of the Stone
Age . These peoples probably lived in bands of about 100, fishing and hunting
herd animals such as reindeer and mammoths. These peoples probably were
nomadic, moving camp at least several times each year to take advantage of
seasonal sources of food. It is likely that they gathered each summer for a few
weeks with other bands to celebrate religious ceremonies and to trade, compete
in sports, gamble, and visit one another. At such gatherings, valuable
information could be obtained about new sources of food or raw materials (such
as stone for tools). Such news might have led families to move into new
territory, eventually into Alaska and then farther south into the Americas.
Evidence for the
earliest migrations into the Americas is scarce and usually not as clear as
archaeologists would wish. Evidence from the comparative study of Native
American languages, as well as analysis of some genetic materials, suggest that
these earliest migrations may have taken place around 30,000 years ago. More
direct evidence from archaeological sites places the date somewhat later. For
example, in the Yukon, in what is now Canada, bone tools have been discovered
that have been radiocarbon-dated to 22,000 BC.
Campfire remains in the Valley of Mexico, in central Mexico, have been
radiocarbon-dated to 21,000 BC,
and a few chips of stone tools have been found near the hearths, indicating the
presence of humans at that time. In a cave in the Andes Mountains of Peru, near
Ayacucho, archaeologists have found stone tools and butchered animal bones that
have been dated to 18,000 BC. A cave in Idaho, in the United
States, contains similar evidence—stone tools and butchered bone—dated to
12,500 BC. In none of these sites
do distinctive American styles characterize the artefacts (manufactured
objects such as tools). Artefacts having the earliest distinctive American
styles appeared about 11,000 BC
and are known as Clovis stone blades.