American Indian, also called Indian, Native American, indigenous American, aboriginal American, Amerindian, or Amerind, member of any of the aboriginal peoples of the Western Hemisphere. Eskimos (Inuit and Yupik/Yupiit) and Aleuts are often excluded from this category because their closest genetic and cultural relations were and are with other Arctic peoples rather than with the groups to their south.

The ancestors of contemporary American Indians were members of nomadic hunting and gathering cultures. These peoples traveled in small family-based bands that moved from Asia to North America during the last ice age; from approximately 30,000–12,000 years ago.

Discussions of indigenous cultures are often organized geographically. The Western Hemisphere typically comprises three regions: Northern America (the present-day United States and Canada), Middle America (present-day Mexico and Central America), and South America.

The earliest ancestors of Native Americans are known as Paleo-Indians. They shared certain cultural traits with their Asian contemporaries, such as the use of fire and domesticated dogs; they do not seem to have used other Old World technologies such as grazing animals, domesticated plants, and the wheel.

Archaeological evidence indicates that Paleo-Indians traveling in the interior of Northern America hunted Pleistocene fauna such as woolly mammoths (Mammuthus species), giant ground sloths (Megatherium species), and a very large species of bison (Bison antiquus); those traveling down the coast subsisted on fish, shellfish, and other maritime products. Plant foods undoubtedly contributed to the Paleo-Indian diet, although the periglacial environment would have narrowed their quantities and varieties to some extent.

Beginning some 11,500 years ago, the climate in the Northern Hemisphere slowly became warmer and drier. Temperatures rose significantly over the next several thousand years, eventually averaging a few degrees higher than those experienced in the same areas during the early 21st century. Cold-adapted plant species such as birch and spruce retreated to the mountains far the north.
Very large animals such as mammoths and giant ground sloths were unable to cope with the change and became extinct; other species, such as bison, survived by becoming smaller.

Spain, France, England, and Russia colonized Northern America for reasons that differed from one another’s and that were reflected in their formal policies concerning indigenous peoples. The Spanish colonized the Southeast, the Southwest, and California. Their goal was to create a local peasant class; indigenous peoples were missionized, relocated, and forced to work for the Spanish crown and church, all under threat of force.

The English, by contrast, sought territorial expansion; focusing their initial occupation on the mid- and north-Atlantic coasts and Hudson Bay, they prohibited marriage between British subjects and indigenous peoples