The first people to occupy the American continents probably arrived from Asia, having crossed the Bering land bridge between Siberia and Alaska as early as 15,000 years ago. This area is covered in water now, but during the last Ice Age, when massive glaciers absorbed enough of the land's water to allow for open areas to be crossed on foot, it would have been a dry tract of land open to the migrations of nomadic hunters and the herds of animals they sought for food. If the original Americans entered the new land by way of this passage, then it is logical to assume that the earliest archaeological evidence of their presence would be found in Alaska, Canada, and the American plains along their routes of migration. Some archaeological sites dating to these first waves of migration between 15,000 and 10,000 years ago have been discovered in these northern reaches of the continent, such as at Blackwater Draw, but because of the arbitrary aspect of preservation and archaeological discovery, the very earliest sites that document the Americas first inhabitants occur in the southern region of South America.
As human populations migrated to the Americas from Asia, the world's climate was undergoing considerable change. These changes forced the nomadic hunters to adapt to new ways of life and new sources of food. In South America, human populations had to deal with the harsh rigors of the prevailing climate and, perhaps as a consequence, occupied different parts of the great continent at intervals depending on the availability of food and adequate shelter. In some regions, the occupants coexisted with such soon-to-be-extinct animals as mastodons and giant ground sloths, and the tools they used were of wood, bone, and stone. Diverse parts of what is now Chile were inhabited, with living sites within the marshes at Monte Verde (10,500-9500 B.C.) in the south-central region, and drier areas such as Fell's Cave (9000-8000 B.C.) in Patagonia.
Fell's Cave, a rock shelter in the valley of the Río Chico not far from the Strait of Magellan, was initially occupied by hunters around 10,000 B.C. who left behind an impressive layer of refuse. Sealed by hundreds of pounds of debris from the fall of the shelter overhang, the hunter's refuse included firepots with the broken bones of native horse, sloth, and guanaco, as well as stone and bone tools. Among the stone tools were fishtail spearpoints, a form of stone point found in many places in South America. Fishtail points are flaked bifacially (that is, worked on both sides) and have pronounced shoulders above a clearly shaped stem. Some are fluted with small channels removed from the bottom. In 1936-37, the discoveries in Fell's Cave represented the first evidence of early humans in South America. Since then, older sites such as Monte Verde have been identified.
Monte Verde in Chile, which was occupied some 14,500 years ago, provides a slightly different view of life for the early inhabitants of South America. Due to the quality of preservation at Monte Verde, natural materials such as wood, fiber, and cordage remain. Even a human footprint has been found there. This range of artifacts crafted from perishable materials is typically lost to archaeologists. Their preservation due to the extremely wet conditions at Monte Verde indicate that baskets, fishing nets, and tents made from hides were among the range of belongings used by the thirty or so people who lived there. These campers were likely able fishermen and gatherers of wild plants, which would have supplemented their diet of hunted animals. They also crafted exquisite leaf-shaped spearpoints. These weapons and hunting tools are not dissimilar from the examples illustrated here from Fell's Cave, which suggests that the two sites, while separated in time by more than 4,000 years, were part of a long-standing and connected tradition of thriving in the new world.