Sometime around 15,000 years ago, the glacial ice sheets that covered northern North America for thousands of years began to retreat. This allowed people living on the other side of the ice in Beringia, the region between the continental areas now known as Alaska and Siberia, to enter North America. The land bridge between the continents at that time was large because so much water was taken up in glacial ice that sea levels were much lower than today. With the retraction of the ice, the Asian people living in Beringia entered North America either along the Pacific coast or somewhat later through a corridor in the glacial ice. By a little over 14,000 years ago these pioneering first peoples had reached the southern areas of South America. The melting glacial ice caused sea levels to rise, submersing and closing the Bering land bridge 10,000-11,000 years ago.
Pedersen et al 2016, Nature
These first peoples, or Paleo-Indians, lived by gathering wild plants and hunting animals. They arrived with a fairly modest toolkit, but by about 13,000 years ago they had developed a lethal stone point named after its place of discovery, Clovis, that made hunting much more efficient. Clovis hunters and their successors using similar fluted points called Folsom, may have hunted to extinction some animals of the American megafauna: mammoth, mastodon, horse, giant sloth, giant beaver, camels and other animals. Climate and environmental stresses might also have played a role in the extinctions, which included carnivores such as Dire wolf, short-faced bear, American lion and saber-toothed cat. It is likely that the first Americans brought basketry technology with them from Beringia. The earliest basketry in North America dates to around 13,000 years ago.
Extinct Columbian Mammoth (Mammuthus columbi). Background: Extinct North American Horse (Equus idahoensis). Arizona Museum of Natural History
Extinct American Lion ((Panthera atrox). Background: Arizona Museum of Natural History
After the end of the big game hunting traditions, by about 10,000 years ago, peoples in both North and South America increasingly adapted their hunting and gathering strategies to a wide variety of local conditions. These Archaic cultures began the domestication of animals and plants beginning about 8,500 years ago, which ultimately led to diverse agricultural strategies and the development of settled village life and division of labor, and ultimately to the civilizations of the Americas. The earliest ceramics in the Americas may be from the lower Amazon region dating between 7,000 and 8,000 years ago.