Knowledge Advances

“Ever since Thomas Jefferson began collecting Native American artifacts and displaying them in his foyer, many theories have been proposed to explain how people first came to North and South America. The most widely accepted was the Clovis-first theory, named for the elegant, fluted spear points found in association with the remains of mammoths, bison and other animals near Clovis, New Mexico, in 1932...

“In the 1960s and early 1970s the ecologist Paul S. Martin and the geoarchaeologist C. Vance Haynes Jr., together with James E. Mossiman, began to develop a dramatic theory about how the Americas were settled. They hypothesized that about 11,500 years ago, at the end of the most recent Ice Age, a single band of mammoth hunters from Siberia crossed the Bering land bridge into Alaska, and from there began spreading across North America. According to this theory, there were no people in the New World until that time. The new arrivals and their descendents prospered and, in just a few centuries, purportedly settled two continents.

“The Clovis-first model gained enormous scientific prominence—in fact, to question it was to risk virtual professional suicide... Now, however, thanks to the new archaeological finds and analytical advances, the Clovis-first model has been refuted.

“In 1977 Thomas D. Dillehay began excavating at the Monte Verde site in southern Chile. Dillehay’s work showed Monte Verde to be at least 12,500 years old, and he was widely criticized for challenging the validity of the Clovis-first theory... Three years ago a special team of archaeologists, including avowed skeptics, inspected Monte Verde. The result was vindication: the experts confirmed that Monte Verde was a legitimate pre-Clovis site... Other sites—and there were many—that had been in limbo because they seemed to predate Clovis could now be acknowledged...

“Not only has the idea that the Americas were devoid of people until 11,500 years ago been disproved, but a second important tenet of the Clovis-first theory has also crumbled: the assertion that the Americas were colonized only once. The latest research shows that the New World probably underwent multiple colonizations: instead of originating in a small area of northeast Siberia, as predicted by the Clovis-first model, the first Americans probably came from many parts of Eurasia.

“Perhaps the nail in the coffin for the Clovis-first theory is that no Clovis-style artifacts have ever been retrieved from archaeological sites in Siberia...

“The idea that the Americas were settled more than once and by different groups of people is supported by evidence from ancient skeletons that been examined with new techniques, such as the study of the DNA in the mitochondria of cells...

“The molecular anthropologist Theodore Schurr and other investigators have identified five distinct mitochondrial lineages, or haplogroups, as they are called, in modern Native Americans. Four of the haplogroups—A, B, C and D—are also found in varying frequencies in different Asian populations, which suggest that early immigrants to the Americas may have come from more than one region of Asia. The fifth haplogroup, known as X, is much rarer than the other four haplogroups, and its origin is not clear. It occurs among certain European populations but is absent in contemporary Asian populations, which suggests that it may record another distinct migration to the Americas, possibly from western Eurasia...

“The advent of the personal computer has enabled Paleo-American investigators to apply powerful statistical techniques to multiple sets of data...

“The work has yielded some tantalizing results that corroborate much of the DNA evidence. For example, the physical anthropologist C. Loring Bruce and his research team have concluded that the modern native peoples of North America are the descendents of at least four different colonizing populations from two different parts of Asia...

“Likewise, the physical anthropologists D. Gentry Steele, Douglas Owsley, Richard L. Jantz and Walter Neves have compiled and analyzed measurements from the earliest known North and South American skeletons. Their research has demonstrated that early New World skulls are quite distinct from the skulls of modern Native Americans...

“The reasons for the difference between early and later New World skulls have yet to be fully explained. The discrepancies may be the result of gradual evolutionary changes that took place over time. On the other hand, the differences may indicate that the early skeletons are unrelated to those of modern Native Americans.

“Thus a radical new idea has emerged: the people who inhabited the Americas when Columbus arrived—the tribes referred to today as Native Americans—may not be descended from the earliest Americans. There is no reason to assume that the first immigrants to the Americas took hold and prospered. Perhaps some of the early colonizing groups died out before later groups arrived. Or it may be that later colonizing groups replaced earlier groups as a result of warfare, the introduction of new diseases, or higher birth or survival rates.”


--Robson Bonnichsen and Alan L. Schneider, “Battle of the Bones,” first published in The Sciences, 2000 July/August